Sunday, October 25, 2009

Would you like a dimpled car?

I was watching the latest episode of Mythbusters with a myth that "A dirty car is much more fuel efficient than a clean car". The theory behind the myth was that a dirty car will have a golf ball like effect (i.e. dimpled golf balls will travel further than smooth ones).

Why do dimpled golf balls travel further?
They travel further because there is less drag to overcome due to a turbulent boundary layer caused by the dimples. (Refer pic below)

Larger drag is experienced by the smooth ball because of a larger wake produced behind it.

Small scale test of the car in the water tunnel using fluorescent dye

Their dimpled car using clay

Take note that it does not take the overall efficiency during the dimpled car test. (i.e. the extra weight does not effect the efficiency)

They did a control test for the undimpled car before dimpling and testing the dimpled one.

The verdict?
Clean car (no clay) = about 26 miles per gallon (mpg)
Dirty car (no clay) = about 24 mpg
Clay + undimpled = about 26 mpg
Clay + dimples = about 29 mpg

So a clean car is definitely better than a dirty car. However, a dimpled car is even better!

Maybe we will see more dimpled transportation or even buildings in the future.

So, would you like one or design one now?

Saturday, October 17, 2009

Defrost!! 2

Just defrosted the fridge at the condo again. As usual, extra thick layers of ice in the freezer.

Before going out for dinner

After coming back from dinner

I dont remember what time I pushed the defrost button but i removed some chunks at about 7pm before going for dinner. Other chunks are still stuck. After dinner, every bit of ice was removed.

In the first picture, ice from the ice maker (or whatever you call that) comes out with the least of effort.

In the process of removing the ice I even got injured a little. Ice from the freezer can be that nasty huh!

Tuesday, October 13, 2009

Men's Brains vs Women's Brain

Someone posted a link to a video on Facebook regarding the topic. Here is the video just in case you guys missed my post on Facebook.

Another similar one by another comedian

Funny and true at the same time. Enjoy =)