I am indicating as 'this property' the properties of Herschel-Bulkley model properties, like yield stress, power law index etc. These are needed to develop this model but in ANSYS fluent only during laminar viscous flow this properties are available in viscosity section of a fluid.
If you want HB properties and turbulent flow then just turn them on at the same time.
Can you tell me what you mean by "fluid property available only during laminar viscous flow". The material property is set separately from the model.
In Ansys fluent it can not be done that's why I am concern about the matter.
"fluid property available only during laminar viscous flow", I mean HB property box is not available during turbulent viscous flow in fluent.
I got that part. However, it is still unclear what property you are referring to.
Hi Rasel, you are right. I checked
You are right. I checked the FLUENT, when I changed the mode to one of the turbulent models such as the k-epsilon model, some viscosity models in the material drop-down box become unavailable. I think it is better to write a UDF code to define the viscosity in any form that you want.
Regards,
Siamak
No, it is not a bug, I found the following sentences in ANSYS Fluent User's Guide:
"ANSYS Fluent provides four options for modeling non-Newtonian flows:
• power law
• Carreau model for pseudo-plastics
• Cross model
• Herschel-Bulkley model for Bingham plastics
Note that the models listed above are not available when modeling turbulent flow."
But I don't know why
Fluent solves non-newtonian fluids in the laminar regime. If you want to solve using a turbulence model then you have to write your own UDF.
I think the reason is that the non-Newtonian fluids -especially viscoplastic ones- are usually high viscose; hence, the Reynolds number is small. In other words, turbulent flow of a HR fluid is not practical.
You have to switch it on manually in console:
/define/models/viscous/turbulence-expert>turb-non-newtonian?.
You'll see an option for NonNewtonian and other models in material's viscosity definition then.
Thank you for sharing your view. You are right, that time when I asked the question I was not sure about this.
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