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June 2, 2016, 22:12 
Compressible vs incompressible SGS model!

#1 
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Yan Zhang
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Hi everyone,
I want to simulate combustion in Internal Combustion Engine with LES. Now I am trying to implement some SGS models to my code. But I found many SGS models are suited for incompressible problems. Fortunately, I found several compressible SGS models: Code:
compressible SGS models: compressible Smagorinsky: [1] Yoshizawa A. Statistical theory for compressible turbulent shear flows, with the application to subgrid modeling[J]. Physics of Fluids(19581988), 1986, 29(7):21522164. dynamic(Germano)compressible Smagorinsky: [2] Moin P, Squires K, Cabot W, et al. A dynamic subgridscale model for compressible turbulence and scalar transport[J]. Physics of Fluids A: Fluid Dynamics, 1991, 3(11):2746. DOI: 10.1063/1.858164. dynamic(Lilly)compressible Smagorinsky: [3] Martνn M P, Piomelli U, Candler G V. SubgridScale Models for Compressible LargeEddy Simulations[J]. Theoretical & Computational Fluid Dynamics, 2000, 13(5):361376. compressible problems. Unfortunately, most of SGS models are incompressible version: Code:
incompressible SGS models: Smagorinsky: [1] Smagorinsky J. General circulation experiments with the primitive equations: I. the basic experiment*[J]. Monthly weather review, 1963, 91(3):99164. Keqn: [2] Yoshizawa A, Horiuti K. A statisticallyderived subgridscale kinetic energy model for the largeeddy simulation of turbulent flows[J]. Journal of the Physical Society of Japan, 1985, 54(54):28342839. dynamic(Germano) Smagorinsky: [3] Germano M, Piomelli U, Moin P, et al. A dynamic subgridscale eddy viscosity model[J]. Physics of Fluids A: Fluid Dynamics (19891993), 1991, 3(7):17601765. dynamic(Lilly) Smagorinsky: [4] Lilly D K. A proposed modification of the Germano subgrid‐scale closure method[J]. Physics of Fluids A Fluid Dynamics, 1992, 4(4):633. dynamicKeqn: [5] Kim WW, Menon S. A new dynamic oneequation subgridscale model for large eddy simulations[J]. AIAA, Aerospace Sciences Meeting and Exhibit, 33 rd, Reno, NV, 1995. dynamicLagrangian: [6] Meneveau C, Lund T S, Cabot W H. A Lagrangian dynamic subgridscale model of turbulence[J]. Journal of Fluid Mechanics, 1996, 319:353385. I don't know: [7] Menon S, Yeung P K, Kim W W. Effect of subgrid models on the computed interscale energy transfer in isotropic turbulence[J]. Computers & Fluids, 1996, 25(2):165180. WALE: [8] Nicoud F, Ducros F. Subgridscale stress modelling based on the square of the velocity gradient tensor[J]. Flow, turbulence and Combustion, 1999, 62(3):183200. dynamic structure1: [9] Pomraning E, Rutland C J. Dynamic oneequation nonviscosity largeeddy simulation model[J]. AIAA journal, 2002, 40(4):689701. dynamic structure2: [10] Chumakov S G, Rutl C J. Dynamic structure subgrid‐scale models for large eddy simulation[J]. International Journal for Numerical Methods in Fluids, 2005, 47(8‐9):911923. I don't know whether these incompressible models can be used to simulate compressible problems. 

June 3, 2016, 04:43 

#2 
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Filippo Maria Denaro
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One of the main difference is in the isotropic term related to div v, for compressible flows you need to supply a model for both isotropic and deviatoric terms.
Have a look here http://www.springer.com/us/book/9789048128181 

June 4, 2016, 03:42 

#3  
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Yan Zhang
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Quote:
I am a firstyear graduate student， and I am just start my research. After reading some papers, I found many people simulate combustion in the internal combustion engine with an incompressible SGS model. I don't know why. I think a compressible SGS model is necessary in such simulation. 

June 4, 2016, 04:08 

#4 
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Filippo Maria Denaro
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it depends on the choice of a lowMach model


June 4, 2016, 04:17 

#5 
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Yan Zhang
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But I never heard Mach number in the cylinder of engine, except for air intake port of engine.
I think the compressibility in the engine is related to the reaction. Reaction causes the big variation of density. As far as I know, we didn't mention Mach number in the cylinder combustion simulation. So, which kind of SGS models should I choose? Maybe incompressilbe model is OK. But compressible model is better. Do I understand this correctly? 

June 4, 2016, 04:31 

#6  
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Filippo Maria Denaro
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Quote:
well, no...for the flow in the cylinder you have a fully compressible case... if you search in google you will find a lot of papers. Try with "LES" and "incylinder" words 

June 4, 2016, 04:43 

#7  
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Yan Zhang
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Quote:
Such as: Code:
[1] Jhavar R, Rutland C J. Using Large Eddy Simulations to Study Mixing Effects in Early Injection Diesel Engine Combustion[J]. 2006. DOI: 10.4271/2006010871. [2] Som S, Senecal P K, Laboratory A N, et al. Comparison of RANS and LES Turbulence Models against Constant Volume Diesel Experiments[J]. 2012. [3] Som S, Longman D E, Luo Z, et al. Simulating Flame LiftOff Characteristics of Diesel and Biodiesel Fuels Using Detailed ChemicalKinetic Mechanisms and Large Eddy Simulation Turbulence Model[J]. Journal of Energy Resources Technology, 2012, 134(3):189206. Now I'm quite confused! 

June 4, 2016, 04:51 

#8 
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Filippo Maria Denaro
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Some studies are related to the valve flowing, without any compression/expansion phase. In such case you can adopt the incompressible model. But if you consider the movement of the piston the compressible effects are relevant.


June 4, 2016, 05:17 

#9  
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Yan Zhang
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Quote:
And, Am I correct now ? 

June 4, 2016, 05:27 

#10 
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Filippo Maria Denaro
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If you have combustion I suppose that the SGS model enters into the other equations... for lowMach model the density variation term can be coupled.
I never worked personally on LES of combustion I suggest following the literature (have a look to the book of Sagaut for reference), your flow problem is often found in the SAE literature 

June 4, 2016, 05:39 

#11  
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Yan Zhang
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Quote:
I have bought that book recently. And I will read it carefully. 

Tags 
compressible, incompressible, large eddy simulation, les, sgs 
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