Does total pressure increases locally in a flow domain for transonic flow conditions

arunjoseph · July 10, 2023, 04:38

I am facing an issue with local increase of total pressure at different location close to LE and downstream TE in a test section simulation with compressor blades using EARSM turbulence model in RANS. The simulation has been converged and also mesh sensitivity studies have been carried out. The inlet conditions have been defined with ambient conditions with 100 kPa. I could see patches of Pt 105 kPa. Can anyone explain me why is so..??

The main goal of the research was to investigate losses and the local increase of Pt affects correct estimation of losses in such configuration.

sbaffini · July 10, 2023, 05:13

What formula are you using for total pressure?

arunjoseph · July 10, 2023, 06:27

I am not sure If I understand you correctly, I am imposing total quantities at inlet using Mach number extrapolated (direction of vectors) and specifying absolute total pressure and temperature on the inlet conditions. The outlet is defined with static pressure imposed.

I am not sure if it a numerical effect of RANS modelling. Because I cannot see any kind of fluctuations on the control points for other quantities at this location.

sbaffini · July 10, 2023, 07:18

You wrote that Pt increases with respect to your inlet values. To even try to understand why it is so, I need the matematical formula you are using for Pt.

Also, is this your code or some commercial CFD code?

FMDenaro · July 10, 2023, 16:37

Quote:

Originally Posted by arunjoseph

I am facing an issue with local increase of total pressure at different location close to LE and downstream TE in a test section simulation with compressor blades using EARSM turbulence model in RANS. The simulation has been converged and also mesh sensitivity studies have been carried out. The inlet conditions have been defined with ambient conditions with 100 kPa. I could see patches of Pt 105 kPa. Can anyone explain me why is so..??

The main goal of the research was to investigate losses and the local increase of Pt affects correct estimation of losses in such configuration.

Have you first tried a simple test case to ensure that the law

p_t=alpha*p, with alpha=[1+0.5*(gamma-1)*M^2]^gamma/(gamma-1)

is verified by your code?

arunjoseph · July 11, 2023, 02:45

The Pt is calculated based on the isentropic relations I guess. The code is ran with a commercial software from Numeca/Cadence known as Fine/Turbo.

July 10, 2023, 04:38	Does total pressure increases locally in a flow domain for transonic flow conditions	#1
arunjoseph New Member Arun Joseph Join Date: Mar 2021 Posts: 3 Rep Power: 5	I am facing an issue with local increase of total pressure at different location close to LE and downstream TE in a test section simulation with compressor blades using EARSM turbulence model in RANS. The simulation has been converged and also mesh sensitivity studies have been carried out. The inlet conditions have been defined with ambient conditions with 100 kPa. I could see patches of Pt 105 kPa. Can anyone explain me why is so..?? The main goal of the research was to investigate losses and the local increase of Pt affects correct estimation of losses in such configuration.

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July 10, 2023, 05:13		#2
sbaffini Senior Member Paolo Lampitella Join Date: Mar 2009 Location: Italy Posts: 2,168 Blog Entries: 29 Rep Power: 39	What formula are you using for total pressure?

July 10, 2023, 06:27		#3
arunjoseph New Member Arun Joseph Join Date: Mar 2021 Posts: 3 Rep Power: 5	I am not sure If I understand you correctly, I am imposing total quantities at inlet using Mach number extrapolated (direction of vectors) and specifying absolute total pressure and temperature on the inlet conditions. The outlet is defined with static pressure imposed. I am not sure if it a numerical effect of RANS modelling. Because I cannot see any kind of fluctuations on the control points for other quantities at this location.

July 10, 2023, 07:18		#4
sbaffini Senior Member Paolo Lampitella Join Date: Mar 2009 Location: Italy Posts: 2,168 Blog Entries: 29 Rep Power: 39	You wrote that Pt increases with respect to your inlet values. To even try to understand why it is so, I need the matematical formula you are using for Pt. Also, is this your code or some commercial CFD code?

July 11, 2023, 02:45		#6
arunjoseph New Member Arun Joseph Join Date: Mar 2021 Posts: 3 Rep Power: 5	The Pt is calculated based on the isentropic relations I guess. The code is ran with a commercial software from Numeca/Cadence known as Fine/Turbo.