There is a well-known equation of state between pressure and density of fluid written as P=B[(rho/rho0)^gamma-1]. Gamma in the equation is different for each material, e.g. water=7.
I am recently working on sunflower oil dynamic simulating. But I couldn't find what value of gamma should be taken. What I have merely known is that 10 is a suitable value of gamma for castor oil. But I'm not sure whether the value could be used in sunflower oil simulating.
Could anyone provide me some information on the value of gamma for different materials.
Thank you very much!
Dear Ming He
Be careful about this item. I don't think it works with this behavior. I'll send you Dr.Crespo thesis. He has expressed this item there. As you know when I worked on sediments, the value of gamma was my problem too and finally I used gamma equal 7 and simulate the sediments behavior as the Bingham fluid.
best regards
in this thesis, he's written the gamma is usually between 1-7. If I'm in mistake I glad to say it and guidance me. thank you
best regards
Dear Pooyan Nikeghbali
Thank you for your suggestion and material.
The commonly-used equation of state (Tait's EOS) P=B[(rho/rho0)^gamma-1] in SPH method, through my investigation, is firstly introduced by Murnaghan (1951) in a paper titled 'Finite deformation of an elastic solid'. Cole (1948) also proposed a very similar one but there's a little difference.
The coefficients B and gamma are obtained with experiments. For a still liquid governed by EOS, the variation of pressure from surface to below is linear while the variation of density is nonlinear. The coefficient gamma controls the curvature of the compression curve, that is to say it controls the degree of nonlinearity of density. Thus, it should be selected according to the material of liquid even though different gamma do not make much distinction in results. As to the coefficient B, it determines the compressibility ability of the fluid. The formula B=c0^2*rho0/gamma is introduced only to make sure a moderate (around 1%) rho/rho0.
So I still believe we should choose a gamma in accordance with the material rather than using a constant 7.
Best regards
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