Swirl component in inflow BC for 2d axisymmetric flows

vishalsacharya · March 2, 2012, 04:19

Hi,

I have used makeAxialMesh by gschaider to create a wedge type mesh for an axisymmetric dump combustor with a cylindrical dump and an annular inlet passage. Since i want to do an axisymmetric simulation with a swirl flow at the inlet, I wanted to know how to setup this BC. Since openfoam works in cartesian, would specifying an out-of-plane velocity component at the inflow make it swirl automatically?

As a second question to this. In case I use a 45 degree sector 3D geometry instead of a wedge and use an inflow where the x,y,z components are resolved for axial and swirl inflow, and set the 0 and 45 degree planes to be cyclic, will i then be able to do the simulation successfully? I guess the point of this question is, cyclic ensures rotational periodicity right? as in, match the normal components to the planes at 0 and 45 degrees?

I appreciate all your views and answers to these.

~Vishal

upadhyay.1 · October 30, 2018, 14:59

Did you get the answer?
Please let me know.

Best Regards,
Ayush

yambanshee · November 2, 2018, 06:33

I don't understand how you would like to simulate a 3d flow (swirl+axial) with a 2d mesh.

Doing so with a 3d mesh is completely possible. Have a look at the pipeCyclic example in the simpleFoam tutorials. Note, an easier inlet boundary would be 'cylindricalInletVelocity'

Cyclic boundaries will correctly model swirling AFAIK as long as you set them up as a rotational cyclic boundary, and correctly specify the rotation axis.

March 2, 2012, 04:19	Swirl component in inflow BC for 2d axisymmetric flows	#1
vishalsacharya Member Vishal Achasrya Join Date: Nov 2011 Posts: 38 Rep Power: 15	Hi, I have used makeAxialMesh by gschaider to create a wedge type mesh for an axisymmetric dump combustor with a cylindrical dump and an annular inlet passage. Since i want to do an axisymmetric simulation with a swirl flow at the inlet, I wanted to know how to setup this BC. Since openfoam works in cartesian, would specifying an out-of-plane velocity component at the inflow make it swirl automatically? As a second question to this. In case I use a 45 degree sector 3D geometry instead of a wedge and use an inflow where the x,y,z components are resolved for axial and swirl inflow, and set the 0 and 45 degree planes to be cyclic, will i then be able to do the simulation successfully? I guess the point of this question is, cyclic ensures rotational periodicity right? as in, match the normal components to the planes at 0 and 45 degrees? I appreciate all your views and answers to these. ~Vishal

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October 30, 2018, 14:59		#2
upadhyay.1 New Member Ayush Join Date: May 2017 Posts: 12 Rep Power: 9	Did you get the answer? Please let me know. Best Regards, Ayush

November 2, 2018, 06:33		#3
yambanshee Senior Member Zander Meiring Join Date: Jul 2018 Posts: 125 Rep Power: 8	I don't understand how you would like to simulate a 3d flow (swirl+axial) with a 2d mesh. Doing so with a 3d mesh is completely possible. Have a look at the pipeCyclic example in the simpleFoam tutorials. Note, an easier inlet boundary would be 'cylindricalInletVelocity' Cyclic boundaries will correctly model swirling AFAIK as long as you set them up as a rotational cyclic boundary, and correctly specify the rotation axis.