[soria]

Hi

I am trying to model the laminar flow past a flat plate and have 3 questions.

1) If I select a constant density and material under the material properties, does this mean that FLUENT is solving the incompressible governing equations? The solution should be comparable to that of Blasius (1908).


2) If I select ideal gas under the material properties, does this mean that FLUENT is using the compressible governing equations? The solution should be comparable to that of van Driest (1952).

3) I am using a symmetry boundary condition for the top of the rectangular computational domain, this imposes a slight streamwise pressure gradient on the laminar flow. Are there any other options I could use to ensure a zero streamwise pressure gradient?


Cheers

Soria

[tas38]

Originally Posted by soria

Hi

I am trying to model the laminar flow past a flat plate and have 3 questions.

1) If I select a constant density and material under the material properties, does this mean that FLUENT is solving the incompressible governing equations? The solution should be comparable to that of Blasius (1908).


2) If I select ideal gas under the material properties, does this mean that FLUENT is using the compressible governing equations? The solution should be comparable to that of van Driest (1952).

3) I am using a symmetry boundary condition for the top of the rectangular computational domain, this imposes a slight streamwise pressure gradient on the laminar flow. Are there any other options I could use to ensure a zero streamwise pressure gradient?


Cheers

Soria

1. Yes and yes
2. Yes and yes
3. I am not sure how the symmetry boundary condition imposed on the upper wall of
the computational domain (normal to the streamwise direction) results in a slight
pressure gradient in the streamwise direction? Seems as though the pressure gradient
may be due to the boundary conditions at inlet and outlet of the domain.

[CeesH]

Doesn't the symmetry mean that basically, you have a domain which represents a flow between 2 flat plates? The small streamwise pressure gradient would then be the pressure drop due to friction right?

Anyway, does the streamwise pressure drop significantly affect the solution?
an alternative may be using a 0-shear wall or a far-field fixed pressure...