Simple question: Time-Dependent RANS vs URANS

c.alanis · January 27, 2015, 14:58

Hello there CFD practicioners,

I have a simple question, however due to the different names given in several scientific papers, i might be a little confused.

1) Is it Time-Dependent RANS the same as URANS (Unsteady RANS)?

2) So, if i am setting a transient/time-dependent study using a commercial code which claims to use the RANS model... Is it actually being solved using the URANS model?

FMDenaro · January 27, 2015, 17:00

Quote:

Originally Posted by c.alanis

Hello there CFD practicioners,

I have a simple question, however due to the different names given in several scientific papers, i might be a little confused.

1) Is it Time-Dependent RANS the same as URANS (Unsteady RANS)?

2) So, if i am setting a transient/time-dependent study using a commercial code which claims to use the RANS model... Is it actually being solved using the URANS model?

RANS is - by definition - a statistical formulation only for steady fields. URANS is used when a specifing forcing term at well isolated time-frequency is present (e.g., the motion of a piston in a cylinder)

spl · January 28, 2015, 11:29

Hi Claudio

URANS is just the unsteady form of the RANS equation i.e. the variables are a function of space and time. So yes a RANS commercial code with the unsteady/transient setting applied is a URANS formulation.

c.alanis · January 28, 2015, 13:10

Thank you for your replies.

January 27, 2015, 14:58	Simple question: Time-Dependent RANS vs URANS	#1
c.alanis New Member Alberto Alanis Join Date: Jan 2015 Posts: 2 Rep Power: 0	Hello there CFD practicioners, I have a simple question, however due to the different names given in several scientific papers, i might be a little confused. 1) Is it Time-Dependent RANS the same as URANS (Unsteady RANS)? 2) So, if i am setting a transient/time-dependent study using a commercial code which claims to use the RANS model... Is it actually being solved using the URANS model?

January 28, 2015, 11:29		#3
spl Member spl Join Date: Nov 2014 Posts: 33 Rep Power: 12	Hi Claudio URANS is just the unsteady form of the RANS equation i.e. the variables are a function of space and time. So yes a RANS commercial code with the unsteady/transient setting applied is a URANS formulation. soheil_r7 likes this.

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January 28, 2015, 13:10		#4
c.alanis New Member Alberto Alanis Join Date: Jan 2015 Posts: 2 Rep Power: 0	Thank you for your replies.