Natural convection in annulus

venkatnv · July 23, 2014, 02:01

I am trying to validate the natural convection in annular flow between a hot inner circular cylinder and a cold outer square cylinder. Please let me know which solver is to be used for this problem and also how to implement the calculation of averaged Nusselt number in the solver.

jherb · July 23, 2014, 04:31

Have a look at the buoyantSimpleFoam (or ...Pimple... for transient cases). Also if the density is not changing much you might want to use buoyantBoussinesqSimpleFoam.

(Have a look at their corresponding tutorials. Be careful with the definition of pressure with differs between the Boussinesq and non-Boussinesqsolvers solvers)

venkatnv · July 23, 2014, 05:11

I tried both buoyantSimpleFoam and buoyantBoussinesqSimpleFoam. I'm trying to validate the case for different Rayleigh's number (10^4 , 10^6). I find that only in the latter solver there is an option to provide the values of the parameters involved in Rayleigh Number( i.e, Beta, Prandtl Number, nu, etc., in the transportPropertes file). So I solved using the latter solver but my results are not matching with the ones in the reference paper. Please let me know where I might be going wrong.

jherb · July 30, 2014, 08:32

For buoyantSimpleFoam you can specify polynomial relations in thermophysicalProperties for these quantities.
http://www.openfoam.org/version2.2.0/thermophysical.php

July 23, 2014, 02:01	Natural convection in annulus	#1
venkatnv New Member Venkataraman Join Date: Jul 2014 Posts: 2 Rep Power: 0	I am trying to validate the natural convection in annular flow between a hot inner circular cylinder and a cold outer square cylinder. Please let me know which solver is to be used for this problem and also how to implement the calculation of averaged Nusselt number in the solver.

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July 23, 2014, 04:31		#2
jherb Senior Member Joachim Herb Join Date: Sep 2010 Posts: 650 Rep Power: 21	Have a look at the buoyantSimpleFoam (or ...Pimple... for transient cases). Also if the density is not changing much you might want to use buoyantBoussinesqSimpleFoam. (Have a look at their corresponding tutorials. Be careful with the definition of pressure with differs between the Boussinesq and non-Boussinesqsolvers solvers)

July 23, 2014, 05:11		#3
venkatnv New Member Venkataraman Join Date: Jul 2014 Posts: 2 Rep Power: 0	I tried both buoyantSimpleFoam and buoyantBoussinesqSimpleFoam. I'm trying to validate the case for different Rayleigh's number (10^4 , 10^6). I find that only in the latter solver there is an option to provide the values of the parameters involved in Rayleigh Number( i.e, Beta, Prandtl Number, nu, etc., in the transportPropertes file). So I solved using the latter solver but my results are not matching with the ones in the reference paper. Please let me know where I might be going wrong.

July 30, 2014, 08:32		#4
jherb Senior Member Joachim Herb Join Date: Sep 2010 Posts: 650 Rep Power: 21	For buoyantSimpleFoam you can specify polynomial relations in thermophysicalProperties for these quantities. http://www.openfoam.org/version2.2.0/thermophysical.php