What Equation Combines Laplacian and Time Derivatives of a Vector Function?

[Schreiberdk]

Hi PF

I need help with identifying an equation. It contains the following:

The sum of: The laplacian of a vectorfunction, the second time derivative of a vectorfunction and the first time derivative of a vectorfunction, which is all equal to zero.

Laplacian(V)+d^2/dt^2(V)+d/dt(V)=0

Anyone got any suggestions, of which equation this might look like, or any specific physical uses of the equation?

 

[AiRAVATA]

It is the Newton equation for the small displacement of a string (or membrane, etc.) considering friction.

 

[Schreiberdk]

So it is a wave equation taking friction into account?

 

[AiRAVATA]

Indeed.---EDIT---

Err, not quite. I hadn't noticed the sign of the Laplacian.