Learning Forum

[omkarmadhekar]

[Aitor]

Why do you use ANSYS Meshing for a 3D model? Fluent meshing has many advantages. For example:n1) Polyhedral elements: Due to the multiple shapes available, they adapt well to complex geometries, so that the mesh quality is high and the cell count is reduced with respect to hexaedra or tetraedra. Moreover, the poly-hexcore method combines the mentioned advamntages of polyhedra and the advantages of hexaedra (low numerical diffusion and best mesh quality).n2) It is easier to use.n3) The quality of the boundary layers is higher.n

[omkarmadhekar]

Please could you send me some links for fluent meshing n

[omkarmadhekar]

The fluid is air N i don't know how to change the watertight geometry meshing into other meshing methodsn

[Aitor]

Do you have any problem with Watertight geometry? nFluent Meshing is highly intuitive. If you have questions, you can ask them here.nIn regards to your mesh from ANSYS Meshing, it seems ok to me. n

[omkarmadhekar]

nope, i don't have any problem with it. n

[Aitor]

Do you have any problem? = Are you encountering any problem when selecting this option? The message maybe sounds rude.nIn Fluent Meshing there are two options available: watertight geometry and fault-tolerant geometry. In principle, fault-tolerant geometry workflow is used when the mesh has defects as spaces, even though I have never used it.n

[omkarmadhekar]

I m not getting any problem with the watertight geometry and also the meshing in fluent.I m not understanding one thing. nI m doing this numerical in a Density-based solver. nmaterial air (Ideal gas) Viscosity - Sutherland.nCell zone conditions Fluid domain - Fluid nBoundary condition asnInlet mass flow inlet nOutlet - Pressure outlet. nWall - wall nfluid domain- interiornBut I m getting divergence error in the solution** I need to check that if the pressure is 4 bar at the inlet. n

[omkarmadhekar]

here I changed continuity to 1e-6 n

[Rob]

Have you enough mesh to resolve the flow? Why are you using the density based solver? What are your boundary conditions? Can you refrain from multi-posting in future? n

[omkarmadhekar]

Yes sorry for double posting. It happened due to the network issue n

[omkarmadhekar]

Boundary conditions Inlet pressure from 4 bar to 10 bar gauge. Outlet pressure 1 bar absolute. I need to calculate the mass flow rate. But as my solution was diverging for these Boundary conditions I decided to take mass flow inlet and pressure outlet. and try to solve the numerical. But the same divergence problem is occurring. I also want to check whether the flow is supersonic or not that's Why I m using a density-based solver. Steady-state condition. n

[Rob]

Pressure based is good for Mach 2-3 and higher if the shocks don't interact too much. You will also need to provide a good initial solution as the local pressure will have a significant effect on the flow. Read up on using adaption registers to patch values into the initial solution. n

[omkarmadhekar]

Please could explain this Adaption registry point and patch solution point in more detail. n

[Rob]

Please read the manual, you create a register and then add in pressure, flow etc to give you a better starting condition. n

[omkarmadhekar]

Why is it not possible to add the value n

[Rob]

That adapts on the pressure field. You need to create regions to add the pressure field in more detail. n