Learning Forum

[ashiadarsh]

In ANSYS Meshing I set a fixed no. of divisions in the x and y directions with biasing in the Y-direction.Now for a grid independence study I can double the no. of divsions in the x and y diections..in that case do i need to change the bias factor?what will happen to the wall Y plus for the second case?Does it change my solution?

[Keyur Kanade]

when you double no. of divisions - 

if you want same first cell height, then you will need to change bias factor. 

if you dont want same first cell height, you need not to change bias factor. it will reduce first cell height. 

 

[ashiadarsh]

So what would you recommend for a grid independence study?I think reducing the first cell height wont create any problem to the solution

[Keyur Kanade]

it depends on what models you use. 

[raul.raghav]

If you double the number of divisions and keep the same bias factor, your first cell height would be halved, or in other words, your Yplus would be halved.

Reducing your first cell height would not cause any problem to your solution, however, you would be unnecessarily wasting grid points in a region which is already well resolved and the gradients are captured accurately.

However, when you double your number of divisions, you can safely half your bias factor and still maintain a Yplus value lower than the previous mesh.