Hi,

I have a question regarding ship wakes, we use standard k-e model as a turbulance model. Can we use spalart allmaras model to decrease the time needed to solve the problem? Timewise I need the efficient model in solving ship wakes with Fluent.

Regards,

Zeynep

is there a free surface or not? anyway, i think k-e will be the worst choice for such a very complex phenomena like a ship wake and spalart-allmaras can give a better solution then k-e. i had seen a paper about a viscous submarine case that showed the spalart-allmaras model agrees well with testing results...

although v2f, des (combination of les and spalart allmaras)and les models must be searched for greater accuracy if there is a warship case etc. but they are expensive to solve also.

kolay gelsin,

burakreis

hi,

thanks a lot for the information. I have another question regarding this study, there is free surface and wave phenomena while solving this problem. Timewise I believe, the turbulence model, is important. Spalart Allmaras is good for aerospace applications, can we still use it for ship wakes with free surface?

regards,

Zeynep

Hi, make sure you have loads of mesh in the Free surface region, especially if you are trying to capture the wake. This is a real difficulty area as results soon difuse and the waves disappear. I'll try and dig out a hydrodynamics paper that goes into detials of requirements for capturing these phenomenon if you are interested. Basically - loads of mesh and high order. Pannel methods work well at capturing these effects. Bob

Hi,

Bob, I'll be very grateful if you send me a copy of the paper you have mentioned. Thank you very much.

Regards,

Zeynep

P.S. which turbulence model will give results sooner and of course accurate when dealing with ship wakes with the free surface inclusion? we use double model, segregated, vof and k-e turbulence model, but I'm curious about the Spalart Allmaras one equation model? I know it is better in aerosopace applications, however can we use for our ship wake simulations?