streamlines
 

hi there, i want to calculate streamlines from a given velocity field. where can i get information on the boundary conditions of the laplace equation thank you ulrich

Re: streamlines
 

At the wall you can set the value of stream function equal zero.

Re: streamlines
 

ok, this is evident (thank ypo anyway).

if i have symetry or von neumann boundary conditions, i impose the gradient of the stream function; unfortunately my conjugate gradient algorithm does not converge in these cases.

Re: streamlines
 

You don't have to solve the Laplace eq. if you already knew the velocity field (assume 2-D incompressible). You can simply integrete the velocity along the grid line from the solid boundary to get the stream function(sf = int[udy-vdx])at each grid point. This may not be very accurate, but certainly very simple.