So, in this lecture and the next possibly couple of lectures, we will be looking at flow, compressible flow through a passage of finite but varying cross sectional area, which is representative of flow through nozzles, diffuses and blade passages in turbo machines. In whatever we have discussed so far, you would have noticed that the area of the stream tube never really appeared in any of the calculations or derivations. We just said that it was one-dimensional flow and so you can probably think of the area of the stream tube to be arbitrary. So, it never appears in any of the calculations but now because we have a passage with a finite and varying cross sectional area, the area of the stream tube is well known. So, for example, if you look at this nozzle, the stream tube for example, from inlet to outlet would just be something like this that would be a stream tube. So, now you can easily imagine that the cross sectional area has to appear in the governing equation. So, there may be there are likely to be modifications in the governing equation. So, let us take a look at this. Now, the problem, the main difficulty that arises in this case is that the flow is no longer strictly one-dimensional. So, if you look at this geometry and if for example, you sketch a few velocity vectors, let us say at any cross section, maybe at this cross section, if you sketch a few velocity vectors. So, along the central line, velocity vector would be horizontal. It will have only one component.  So, as you go up towards the wall, the velocity vectors would start to sort of turn like this and eventually, they become parallel to the wall. So, in the same way as you go like this, so the velocity vectors become parallel. So, if you look at the velocity vectors here, we can see that it is a two-dimensional flow, two components of velocity are non-zero. So, two components. So, strictly speaking, this is not a one-dimensional flow, but actually a two-dimensional flow. So, that is the main difficulty that arises now compared with what we have done so far. Now, the variation in the cross sectional area is in a direction normal to the main flow direction. So, the velocity component in the normal direction is non-zero and that is what we are seeing here. So, you can see that this has two components of velocity, one along the flow direction and one perpendicular to the flow direction. So, this becomes non-zero. However, what happens in most of the applications that involve these kinds of varying area passages is that the stream wise component of velocity is much, much larger than the normal component of velocity. So, if I denote the x component of velocity as Vx and the y component of velocity as Vy where this is x and this is y, then it turns out that usually Vx is much, much larger than Vy. Now, as the nozzle becomes longer and longer, of course, Vy becomes larger and larger. So, for example, in the case of a rocket nozzle where the area between area ratio between the exit and the throat could be of the order of 100 which is quite high, the normal component of velocity itself would be of the order of maybe couple of 100 meter per second. But the stream wise component of velocity in such cases is likely to be the order of 1.2 to 1.5 kilometer per second. So, that is much, much larger than the normal component. So, that is the most important observation that we make in these sorts of applications flow through varying passages, varying area passages, I am sorry. So, the normal component of velocity is small when compared with the axial component. So, as a first approximation, we ignore the normal, the normal component and simply treat this as approximately one-dimensional or quasi one-dimensional. So, this is not strictly one-dimensional, it is strictly two-dimensional, but we will neglect the y component of velocity and treat this as approximately one-dimensional. So, such flows are called quasi one-dimensional flows. So, let me just clean up this diagram a little bit. So, governing equations for the for this flow in differential form, they are identical to what we had before. The differential form of the governing equations are almost identical. You will notice that area appears in this in the continuity equation. So, almost identical to what we had before and we treat the flow as isentropic unless there is a normal shock somewhere in the divergent portion. So, we will see that a normal shock is likely to occur in the divergent portion of the nozzle. So, the flow is considered to be isentropic. So, if I call this station x and I call this y. So, for the normal shock, of course, we know that entropy increases across the normal shock. So, S y is greater than S x, but the flow itself is taken to be isentropic with entropy S x in this portion and isentropic following the normal shock and the entropy increases across the normal shock. So, that is a discontinuous increase in the entropy across the normal shock. Otherwise, the flow is considered to be isentropic. Now, if I apply the governing equation between two stations, let us use a slightly different color here. So, let us say I apply the governing equation between stations, let us say 1, let us call this 1 and let us call this 2. Then the continuity equation looks like this, which is fine, but the momentum equation, notice that the momentum equation is slightly more complicated than the differential form led us to believe. The differential form is same as what we had before, but the momentum equation in finite form looks this way, especially this term is very different. This comes from the fact that momentum balance now has to take into account the force exerted on the fluid by the walls of the nozzle. So, this is the stream tube that we are considering and we are applying the momentum equation across this stream tube. So, the force exerted by the nozzle surface on the fluid along this control volume has to be taken into account. So, that is what this term brings in. Energy equation looks the same as before, S2 is equal to S1. So, please make sure that you understand the change in the finite form of the governing equation versus the differential form of the governing equation. Now, the differential form of the continuity equation, you will recall, look like this, rho times V times A equal to 0. So, if you use product rule, expand and then divide by rho times V times A, you end up with this form for the continuity equation. And if I take a quantity like this d rho over rho, which is the first term here. So, d rho over rho may be written as d rho over dp times dp over d rho. And this quantity itself is equal to 1 over A square. And I can substitute for dp from my momentum equation like this dp equal to minus rho V dV. So, I end up with this expression for d rho over rho, where m is equal to V over A. And if I plug this back into my original equation, I end up with this expression dA over A equal to m square minus 1 times dV over V, which is a very, very important relationship in flows through passages with varying area. This is called the area velocity relation, because it involves the area obviously and the velocity. So, it is called the area velocity relation. So, basically what this says is the following. If I have, so we can imagine, let us say several situations. Let us say subsonic flow and let us say supersonic flow. So, if I look at passage, let us say converging passage in supersonic flow and subsonic flow, what is that? In this case, since dA is negative, the passage is converging, dA is negative. This tells me that dV is going to be, so if you look at this, dA is negative. And in the case of subsonic flow, this is also negative, which then tells me that dV has to be positive. So, V increases in this case, the velocity increases. Now, in the case of supersonic flow, dA remains to be negative, because it is a converging passage. But now, m square minus 1 term is positive because m is greater than 1, which means that dV has to be negative. So, supersonic flow actually decelerates in a converging passage. So, in the same manner, we can show that in case it is a diverging passage, so let us, in case it is a diverging passage, then dA is positive. And in the case of subsonic flow, this term is negative, which then means that dV has to be negative. So, a subsonic flow decelerates in a diverging passage and a supersonic flow, so this term becomes positive. So, supersonic flow must accelerate in a diverging passage. That is what we have shown here. So, this is a diverging passage, it is a converging passage, so area decreasing, converging passage, this is a diverging passage. So, subsonic flow in a diverging passage decelerates, subsonic flow in a converging passage accelerates and exact opposite for supersonic flow. This is true whether the fluid is calorically perfect or not, remember we have not used the calorically perfect assumption so far. So, this is true for air, true for steam and true for refrigerant.  So, the question that arises next is what happens when m is equal to 1? So, if you look at this expression, so as m goes to 1, dA has to go to 0. We look at it that way, as m goes to 1, dA has to approach 0 for velocity to remain finite. So, as m goes to 1, dA goes to 0. So, as we allow m to go to 1, dA goes to 0. In fact, dA becomes equal to 0 when m becomes equal to 1 or wherever m becomes equal to 1, dA has to be 0. So, what this says is the following. Remember the flow is still isentropic, isentropic flow in a passage of varying cross-section. The sonic state can be attained only at a location where dA is equal to 0 that is another way of stating this. So, the location can either be a minimum or a maximum in the cross-sectional area. So, dA is 0 at this location or at this station and dA is 0 at this station also. Now, so we have two situations where dA is equal to 0 and let us examine this much more closely. Is there any more that we need to infer from this relationship? So, let us say that m is equal to 1 in this case. If the incoming flow is a subsonic flow, then it will accelerate in a converging passage which is this one here and it will be able to accelerate to m equal to 1 and then the flow will decelerate in the diverging passage which is this one here and it will be able to leave without any difficulty. So, m equal to 1 is possible in this case at the throat. Let us say it is a supersonic flow. Now, of course, in the case of the subsonic flow as I said, it will accelerate here reach m equal to 1 and then depending on the exit condition, it can continue to accelerate and reach supersonic speeds or it will decelerate and remain subsonic. Both exit conditions are possible, subsonic exit condition and supersonic exit conditions are possible which one is realized in actual practice depends upon the exit conditions that are being maintained here. What is the exit pressure that is being maintained at the exit of the nozzle? Now, in the case of supersonic flow, so supersonic flow decelerates in a converging passage which means that it can decelerate and reach m equal to 1 and then supersonic flow actually as you can see here, so it reaches m equal to 1. So, from here onwards again depending on the exit condition, we can either have flow which after reaching m equal to 1, it can decelerate and leave at a subsonic Mach number that is possible or depending on the exit condition, it can accelerate slightly and also leave, it can accelerate and also leave as a supersonic flow at the exit. So, both both exit conditions are possible. But what this says is, you know the m equal to 1 state can be reached by a subsonic flow at entry to the nozzle or by a supersonic flow at entry to the nozzle. That is what this discussion suggests. Now, let us go to this case again, if you assume m equal to 1 in this case, let us say we assume m equal to 1. Let me write this in a different color. So, we assume m to be equal to 1 here. Now, let us say that the incoming flow is subsonic. So, subsonic flow decelerates in a divergent passage like this, which means that it cannot reach m equal to 1. So, it is already subsonic and it decelerates further, which means it cannot attain m equal to 1 at this location here. Now, let us assume the incoming flow to be supersonic. Supersonic flow accelerates in this divergent passage. So, a supersonic flow for which the Mach number is already greater than 1 will accelerate even further to higher values of Mach number. So, it cannot attain m equal to 1 at this location. So, which tells us that when m equal to 1 state or the sonic state is attained, it is always attained at a throat and not at a location like this. This when m reaches 1 at the throat, the condition is known as choking. We will discuss this in a minute. So, the flow is said to be choked and what is important is choking if it occurs can occur only in a geometric throat. That is what we just demonstrated that m equal to 1 is possible only at a throat. Now, please bear in mind that the sonic state if it occurs, it must occur at a geometric throat, but flow need not always choke at a throat. That is very, very important. If m is equal to 1, it must always be at a location where dA is equal to 0 for the velocity to be finite. So, this is a very subtle point and you need to understand this. So, if m is equal to 1 that is on the right hand side, then dA must be 0 for the velocity to be finite. So, if m equal to 1 occurs, then it will always occur at a point at a throat where dA is equal to 0. On the other hand, if dA is 0, then m need not be equal to 1. m can be any value it wants, but dV is equal to 0. dV can be equal to 0. So, if dA is 0, then m need not be 1 there. So, what this means is if m equal to 1 occurs is realized because of the conditions that we are maintaining in the flow, the downstream pressure, upstream stagnation pressure and so on. If the conditions are such that the sonic state is realized, it will always be realized only at the throat. However, the Mach number need not always be 1 at the throat, it can be anything else, again depending on the conditions that are being maintained. So, the so the counterpart or the converse is not always true. If the flow is choked, it will always choke at the throat, but just because there is a throat does not mean that the flow has to be choked there. We will understand or we will give an explanation for why this is called choking as we go along. But for now, we will use the term without paying too much attention to it. Now, we will derive a relation called area Mach number relation. Notice that the previous one was area velocity relation. Now, we will derive something called an area Mach number relation for choked flow of a calorically perfect gas. So, here we are going to make use of the calorically perfect assumption. Whatever we have said so far is valid for calorically perfect as well as fluids which are not calorically perfect. So, let us say that you know we have an also like this. So, the mass flow rate at any section can be related to the mass flow rate at the sonic state. Now, again remember we said that sonic state if it occurs it occurs at the throat, but sonic state need not occur at the throat. So, in this case let us say the sonic state does not occur at the throat. What we would then say as I mentioned in our discussion of the sonic state, we can always extend this to a we can extend this. So, this is an imaginary extension and we would say that the sonic state occurs at this location because it is a location of it is a throat. We can add a convergent section like this and it is a throat. So, the sonic state occurs there or alternatively if the conditions are such that sonic state can be attained here then we can have a sonic state here. So, regardless of whether this sonic state occurs here or here we may write this because it is a same stream tube mass is conserved in this stream tube. So, I may write m dot equal to rho times v times a at this at this station equal to rho star v star times a star either here or there does not matter. So, if you rearrange you can get this expression. So, rho naught over rho may be written in terms of Mach number like this and rho naught over rho star may be written again like this after setting m equal to 1 in this expression. Remember v star is the velocity of the fluid at the throat and since it is a sonic state v star is equal to a. So, if you substitute all these into the equation that we have for a over a star we get this. Now, t star over t may also be written in terms of Mach number like this t star over t is equal to t star over t naught times t naught over t. So, you finally end up with an expression that looks like this a over a star is equal to this which is. So, the right hand side is a function only of Mach number. This is called the area Mach number relationship. So, given the area of the passage the cross sectional location and the value for a star we can determine the Mach number at that location using this relation. Actually this equation gives two values for a given a over a star. For example, if you look at this nozzle let us say that the flow is choked at the throat. Then you can easily see I am sorry let us go here. Let us say that the flow is choked at the throat. Then you can easily see that the Mach number I mean the value for a over a star is the same at these two stations. So, at this station and at this station. However, depending on the pressure if the pressure in the downstream of the nozzle is maintained in such a way that the flow becomes supersonic here and you can see that for the same value of a over a star. Remember here a star is equal to a throat because the flow is choked at the throat. So, for the same value of a star you can see that the flow is subsonic here reaches m equal to 1 here and the flow is supersonic in the divergent portion. So, for the same value of a over a star you can get either a subsonic solution or a supersonic solution and we use whichever one is appropriate. Now, very important a star is equal to the throat area only when the flow is choked. Otherwise as we just showed here a star would be equal to this the throat area of this imaginary extension. If the flow is choked then a star is equal to a throat. Now this function a over a star is listed I am sorry this quantity a over a star is listed as a function of Mach number in the gas table. So, you may use that let us just quickly take a look. So, you can see that not only t naught over t p naught over p rho naught over rho or listed a over a star is also listed. So, both the subsonic solution as well as the supersonic solution are listed for a over a star. Now, we may write the mass flow rate at any section like this m dot equal to rho v a and if I rearrange this by using stagnation quantities as well as the Mach number we may write it like this. So, we basically write this as rho over rho naught and this v is replaced in favor of the Mach number and a is written as a over a star times a star. Remember we are saying choked flow of a calorically perfect gas which means a star is equal to a throat. So, this a over a star may be replaced with the area Mach number relationship. So, if you do that you finally end up with an expression that looks like this. So, m dot equal to p naught a throat divided by square root of t naught times this quantity in this in the inside the square root I am sorry. Notice that this quantity depends only on the nature of the gas. So, or depends on the molecular weight of the gas gamma depends on whether it is diatomic or monatomic. So, a throat is a geometric parameter. So, p 0 and t 0 are the stagnation pressure and stagnation temperature respectively at the inlet to the nozzle that is very very important. This is the stagnation pressure and temperature at the inlet to the nozzle. So, basically we are looking at a situation like this. So, flow comes in at a stagnation pressure of p 0 and t 0 presumably at a subsonic Mach number that is a most common scenario reaches m equal to accelerates to m equal to 1 on the throat and then depending on the exit condition either accelerates or decelerates. We will discuss that in more detail as we go along. So, the mass flow rate at any section in the nozzle whether we take a section whether we take a section here section here or section here or here mass flow rate at any section in the nozzle is equal to this. This is an extremely important expression in flow through nozzles and it determines the operation of not only nozzles, but other components that occur I mean that are encountered in real life where we have multiple components each of which can choke independent of each other. So, this is a very very important expression in gas dynamics. The most striking feature of this expression is that it does not involve any downstream quantity. So, as I said you know the quantity inside the square root depends only on the gas and the quantities this is a geometric quantity and these two p 0 and t 0 on stagnation conditions upstream of the nozzle. So, the downstream conditions are not seen in this expression at all, but yet we are saying that depending on the downstream conditions that we are maintaining the nozzle may be choked or not, but once the nozzle is choked what this is telling is downstream conditions may determine whether the nozzle is choked or not, but once it is choked the mass flow rate is no longer dependent on the downstream condition. It is a very very powerful inference from this expression. So, which means that if I try to adjust the flow through the nozzle by let us say having a controlled downstream of the nozzle I can adjust the flow only as long as the flow is not choked. Once the flow is choked the mass flow rate becomes a constant and it is no longer dependent on the downstream pressure or downstream pressure is sufficient. It is no longer dependent on the downstream condition. The only way to change the mass flow rate through the nozzle in this case is to change p 0 or t 0 without changing the nozzle itself. If you change the throat area then you are changing the nozzle itself without changing the nozzle if you want to increase the mass flow rate for instance then I must increase either p 0 or decrease t 0. This is a very very important inference from this expression. So, this we have already already said. So, once the flow is choked the mass flow rate that can be realized through the passage is dependent only on the upstream stagnation pressure, stagnation temperature and the throat area. This means that the mass flow rate cannot be controlled anymore from downstream that is by adjusting the exit condition. But of course, you cannot adjust the downstream condition so much that the nozzle unchokes. If it unchokes then of course, this expression is no longer applicable. This expression is applicable only when the nozzle is choked and because we assume a star equal to a throat. So, if you change the exit condition so much that the nozzle unchokes then this expression itself is no longer valid. So, that is something that you must keep in mind. In other words, this is the maximum mass flow rate that can be achieved by adjusting the back pressure. This is very important. This is not the maximum mass flow rate that the nozzle can swallow. This is the maximum mass flow rate that the nozzle can swallow by adjusting the back pressure. If I want to increase the mass flow rate beyond this I can simply increase p 0. So, you must bear that in mind. The mass flow rate can be changed at will by an adjustment of the upstream stagnation conditions or the throat area. You can change the throat area or the upstream stagnation conditions. Now, you may be wondering when we would ever want to change the throat area. This actually is a very viable and widely used controlled strategy in case of supersonic inlet, supersonic diffuses or supersonic inlets which are present in the engine of aircraft that fly at supersonic speeds. So, there having a variable throat area diffuses is actually very useful for controlling the flow in the diffuses for choking and unchoking the flow at will. So, variable throat area nozzles are actually available and are quite extensively used in real life applications in aerospace propulsion. Now, the inferences that we have drawn here are applicable whether the substance is calorically perfect or not meaning it can be steam or refrigerant. But the exact expression may not be applicable because we have invoked the calorically perfect assumption. So, whether it is air or steam or refrigerant there is a maximum mass flow rate that can be achieved by controlling the downstream pressure. So, once the nozzle chokes the mass flow rate cannot be changed anymore by changing the downstream condition. And however, the mass flow rate can be changed at will by changing the upstream stagnation pressure or stagnation temperature. Because you must bear in mind that since we are not using or since the calorically perfect assumption cannot be used in conjunction with steam or refrigerant, the notion of a stagnation temperature itself is not meaningful in that case. Stagnation temperature is replaced by the stagnation enthalpy. So, the expression will not be valid for substances which are not calorically perfect, but the inferences are all correct. So, what we will do in the next lecture is to take a closer look at the flow inside nozzle. We will look at two situations convergent nozzle and a convergent divergent nozzle.


acoustics extremely important in a home voice-over studio do we talk about it enough on this show a few times but we're joined here by Ron Knight Ron welcome to our show yeah and you're with Joe Kavi acoustics I've known these guys for about four years now I guess some of your people might remember me from voiceover over the decades and I've started working with this organization because when people were asking me on advice on what am I going to do about my home studio there's a lot more to it than just getting your favorite little USB microphone and patching it into your deck with pro tools and then the next thing you know you're still dealing with the sounds of your room so this organization has got this company around the world for 21 years in about 47 countries has been coming up with great sonic solutions acoustic treatment solutions and to boot needless to say they look pretty doggone good yeah aesthetics is always important to a lot of our clients and these are very different from you know charcoal and purple and that sort of thing not to downplay but a lot of the other off-the-shelf solutions might be available at your typical retail chain your general choice has been gray camel and maybe purple and it's the same plan of five fingers with a little bit of an absorbent form that may do the trick in terms of just drawing up a room and mopping it up but it's not really solving a lot of the other acoustical solutions that you may need to have solved in your voice over I'm looking over here I mean up there's a combination of different stuff we've got obviously diffusers at the bottom but then we have some things up top here that are more of a combination of reflection and absorption right yes correct how would that be an advantage in a small booth well I look at it this way when you're getting your typical off-the-shelf stuff whether it's ultimate market tech some of the other usual suspects that are out there you're coming up with one solution and people just patching it wherever it needs to go the thing about sound is while there's no such thing as sound proofing we do have sound mop up clean up and sound confusion of sound waves and really the more you can confuse a sound wave and mop it up from all of its different respected problems base low end frequencies high end frequencies mid ranges something like this aside from being pretty dug on gorgeous to look at I mean can you imagine if you were recording in your den and you had a whole wall made of something like this and we have a variety of options this is actually doing three different things it's got an inner core of sound absorption within every square on the inside it's got a texture which is also creating that not a parallel wall or that typical thing where you having a reflective surface so sound is going to bounce off of that then what's happening is that by capturing the sound wave in the room it's actually forcing it into a pattern which is then forcing it to get absorbed into the outer shell which is also yet another reflective or absorption type of material so that's all going on with within one panel and a price point on something like this for the voiceover guy gal forty six dollars for a two foot by two foot panel so when you think about just getting something like that and saying how am I going to treat my room I think maybe all of us would agree that's probably a little bit more interesting little five fingers sticking out of the same gushy foamy stuff right that's that's actually an excellent price point you wouldn't need a whole lot of that was going to be a hundred and fifty dollars frankly we do have that as well yeah well this is a much more complex firm does everything from concert halls professional recording studios pavilions theaters the whole gamut you know in terms of restaurants and every other typical isolated sound problem trap but for the home studio person this is probably you know another thing they have is what we call studio kit in a box so somebody says gee my home studio is going to be in my closet it's four foot by six I actually am doing this in a den maybe that's twelve foot by sixteen we have six templates ready to go by size by color and they can literally go say I need a T pick ATP kit number four version number B that gets sent in a box they can just throw it by template right up into their room very nice and that's and that's a that's a really great thing for anybody who really doesn't exactly know what they want to do that they can get a kit like that and you show them how to arrange it we can you know I mean if they really are going to go open up a real prograde studio they were really happy to come on out and show them how to put that together we do that don't we tell us about what's unique about that substrate that that white foam yeah that being used in some of these products yeah this is I mean some vocal people or voiceover people might know what I'm talking about we used to have a New York New Jersey studio which was really busy a lot and we'd step into a little whisper room or something like that and it had a really nice quality more or less to just dampen up the sound but your voice talent would get in there after a while they feel like gee I'm going horse I it feels like I'm getting a scratchiness in the throat literally the joke I've told is we've had people go out get those spray Mr. Bottles and bring it back into the vocal booth trying to get some humidity in there there's a lot of things going on in your recording environment for your throat this is actually used in hospitals this particular foam is an antimicrobial it's hypoallergenic it is antiviral antifungal and this is something they use in a medical environment but at the end of the day you can see the fine cellular weave in that foam as a sound absorptive property it's great but for the vocal person when using this it's pretty doggone great because if you're having issues with your throat this can be a solution is this as effective if not more so than like a typical foam type material again all depends on what's going on in the room when these guys came to my rescue I had a recording studio that was built in the flight path of an airline airport yeah and that had all kinds of issues going on there's a different foam for a different solution absolutely based upon the environment that you're in nice where do you where do we get this stuff where would the typical voice actor go to pick out some of this product oh funny that you mentioned that let me tell you george that's why we're here that's why we're here george i'm the north american rep for this company i do have a site for what it's worth keggtrader.com they can come over there and take a look at the kits in the box but they also have a brand new service which is again mentioning that this company is out of portugal but now in north america they have a little online website called acoustic shop and we can give you a promo code that is the 10 discount going on with nam those people who are in voiceover reach out to me i'll give you a code you get to continue 10 discount for ordering anything online from out of the united states supply awesome that's what i would do that's it sounds like a great deal well ron pleasure to meet you finally we certainly know your name from the voiceover business i've seen your name too out there in the world and i'm glad you guys are blogging and it's nice to meet you george thanks for coming by appreciate it


Hey what's going on guys, it's Mark and I'm back with another tutorial, like eToro guide for beginners like if you're just getting started out. So today I'm going to go over what a pending closes. Any story because that can be quite confusing. Why have I just tried to close my trade and now it's gone into pending and I'm just going to go into kind of all the questions you might potentially have about that. If there's anything that I miss out then feel free to drop me a comment and I'll always get back to you on Instagram, eToro, YouTube. I'll be accessible on all of those. So let's start off with so this is my eToro portfolio right now. I don't have anything that I want to close. So what I'm going to do is I'm going to quickly jump across into my virtual but everything is exactly the same. So it's literally just that it's virtual and not not real so nothing to worry about there. So basically what a pending close on eToro is, it basically means that you've closed your trade but the market for that asset that you're trying to close isn't open right now so it's not able to execute on the trade or make the close happen hence the reason it's a pending close right. So for example Apple is part of, if you go on here you can see it's part of the NASDAQ and then what I'll do is I'll leave a link in the description so it's an eToro page and it shows you the opening times for all the markets so it'll be the forex markets, the cryptocurrency which is 24.7 so you shouldn't have any pending closes there and just all the different indexes that these funds will be part of but I'll show you for example say so basically you go on here you go to close your trade just a quick insurjection from the editing version of me if you don't know how to close trades open trades what buy or a sell position is click the tab in the top right there should be a little pop-up now and that goes into detail about that. Cool. You can see that the market is closed here on the page anyway it will say market closed but we'll go back on the trade real quick go to close your trade and then you can see here no your close order will be executed once the market opens so there's a few warnings that this isn't going to execute straight away and then go ahead and click close trade and then you can see it goes into pending close so for the UK this for Apple in particular the NASDAQ opens at 2 30 pm so as soon as it hits 2 30 pm right now it's like 1 am but as soon as it hits 2 30 pm today this will close and then obviously I'll have the money in my available balance or whatever I want to do with it so that will close at 2 30 and yeah and likewise as I say for whatever the market is is when it will close. Another quick note from me which is quite important when the market opens it will sell or it will close your trade at the opening price so it might not necessarily be the price that you're seeing on the screen. So if Apple falls 10% between the time you close the trade and the opening time of the market it will close your trade at 10% lower than what you're seeing so that's just something to pay attention to and I'll go a little bit into detail about that later on. It's the same for copy trader as well so if you're copying someone and you want to get rid of if you want to stop copying their entire portfolio or parts of it or whatever it might be if you stop copying them you'll probably have a bunch of pending closes which will basically be exactly the same thing once those markets open your close will be executed your close all will happen and then you'll have your available funds again so it's just a case of checking when the markets are open and when that will happen obviously if the market's open then it won't go into pending. So let's say you've done this by accident so you've gone into you've gone to close the trade you don't want to close the trade or you've changed your mind or you've looked at the pre-market and you see that it's going to open and Apple's had some awful news and it's going to be 10% down and you actually just want to hold on to it for the long term you can always come back on to it obviously providing that the market hasn't opened yet and cancel it right so you see this cancel button here and even if we come off of it so if we go on portfolio and refresh it have a look around and then you come back and then go back on to the trade and it's going to be there pending close and then you just go ahead and cancel it and then just goes back to just telling you the details about when you bought it and that sort of stuff but yeah it says using that closed trade wash cancel so that's it really that's everything to do with pending closes if there was any confusion and I think that's everything so it's copy traded covered what pending close is how to cancel a pending close and if you want to know the opening times for all the markets I'll leave a link for that because there's a whole bunch of stuff for in like one of the e-tour FAQs with that being said just a general rule of thumb US markets usually 230 for the UK so if you want to change the time if you want to use a time convert and it's easy if you generally it's 230 the European markets I think it's 9am although I don't get involved with them too much a forex trades from Sunday evening to Friday night I think so Friday 10 and then opens at Sunday 11 p.m. cryptos 24 7 and I think that's everything for now but I hope this was helpful if it was give it a thumbs up share on e-tour I'll probably drop a Sunday tour and tag a bunch of like the beginner markets on this usually for some crypto stuff if you want to copy me by all means go for that or if you just get any questions or want to chat or you know make some friends and message me as well so thanks for watching and I will catch you guys in the next one please out