For 10 points, give this term denoting a type of energy associated with the configuration of a system, such as the energy stored in a compressed spring.
This type of inviscid flow around a cylinder has streamlines that are exactly reproduced outside of a small boundary layer by Hele-Shaw flow.  This type of flow is equivalent to incompressible, irrotational (*) flow, and satisfies Laplace's equation for a namesake function associated with the velocity.  In thermodynamics, this term denotes the internal energy and all Legendre transforms of the internal energy.  In electrodynamics, the Li?ard-Wiechert equations give the retarded forms of two versions of this quantity, and the magnetic field equals the curl of the vector version of this quantity.  Any conservative force can be described as the negative gradient of one of these scalar functions.  For 10 points, give this term denoting a type of energy associated with the configuration of a system, such as the energy stored in a compressed spring.
This type of inviscid flow around a cylinder has streamlines that are exactly reproduced outside of a small boundary layer by Hele-Shaw flow.  
potential [accept incompressible irrotational before (*); do not accept or prompt on incompressible, but suit yourself]