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April 28, 2014, 03:10 
air flow impinge on a hot cylinder

#1 
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Join Date: Mar 2013
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Hi,
I have a problem with a simulation. The flow configuration is as follows: An air flow ( T = 298 K) impinge on a moving cylinder (T = 1873 K; u = 7 m/s). The boundaries around are no walls but rather open atmosphere. The aim is to detect a possible buoyancy flow because of the temperature differences. The air at the calculation area has a temperature about 323 K. The solvers I chose are "rhoPimpleFoam" and "buoyantPimpleFoam". First question: Are these the right solver or is there another better one? The main problem affects the boundaries (to the atmosphere). I chose it as follows: p: boundary_to_atmosphere { type fixedValue; // OR type calculated; value $internalField; // internalField is about 1e5 } p_rgh: boundary_to_atmosphere { type fixedFluxPressure; value uniform 1e5; } T: boundary_to_atmosphere { type inletOutlet; value uniform 323; inletValue uniform 323; } U: boundary_to_atmosphere { type pressureInletOutletVelocity; value uniform (0 0 0); } I think I did a mistake because I get a temperature lower than 273 at the internalField. Second question: Are the boundaries correct? Third question: In the "thermophysicalProperties" I chose thermoType { type heRhoThermo; mixture pureMixture; transport const; thermo hConst; equationOfState perfectGas; specie specie; energy sensibleEnthalpy;//sensibleInternalEnergy;//sensibleEnthalpy; } Is this correct for this type of flow? I use OpenFoam 2.3.x I hope somebody can help me. Best regards, dbnrop 

April 28, 2014, 09:30 

#2  
Member
Andrew Somorjai
Join Date: May 2013
Posts: 77
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Quote:
I'm almost 100% positive buoyantPimpleFoam is the best for this. For the pressure I think you need type calculated; because p_rgh calculates pressure in the hotRoom example. You would also need to setup probes (an example can be found in the TJunction tutorial in the controlDict file). That's all I know. 

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