Boundary conditions

minnymoony · August 18, 2009, 05:25

Hi,
I'm taking a CFD class at university and have to write a code (in matlab) to solve the flow in a 2-D nozzle.The nozzle is symmetric so i'm solving only halve.

What i'm not sure of now is how exactly to write the boundary conditions
on the symmetry plane. is it enough to say that the pressure (and u,v,rho)
on the symmetry plane are the same as on one 'line' above? rho(i_max,

=rho(i_max-1,

?

Does any one know of a code that I can look at and compare (i'm using Beam & Warming method)?

Thanks.

otd · August 18, 2009, 14:22

It would seem that the symmetry condition requires no mass flow across the symmetry boundary (velocity normal to boundary = 0). In some algorithms that may imply the pressure gradient = 0, very similar to making the pressure the same on either side of the symmetry plane.

August 18, 2009, 05:25	Boundary conditions	#1
minnymoony New Member Emanuel Join Date: Aug 2009 Posts: 2 Rep Power: 0	Hi, I'm taking a CFD class at university and have to write a code (in matlab) to solve the flow in a 2-D nozzle.The nozzle is symmetric so i'm solving only halve. What i'm not sure of now is how exactly to write the boundary conditions on the symmetry plane. is it enough to say that the pressure (and u,v,rho) on the symmetry plane are the same as on one 'line' above? rho(i_max,=rho(i_max-1,? Does any one know of a code that I can look at and compare (i'm using Beam & Warming method)? Thanks.

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August 18, 2009, 14:22		#2
otd Member private Join Date: Mar 2009 Posts: 74 Rep Power: 17	It would seem that the symmetry condition requires no mass flow across the symmetry boundary (velocity normal to boundary = 0). In some algorithms that may imply the pressure gradient = 0, very similar to making the pressure the same on either side of the symmetry plane.