Why does U_{LB} depend physical dimensionality of problemy at LBM??

Hi community,

I have a question about of U_ {LB} at palabos. I simulated a channel 2D (D2Q9) and 3D (D3Q27), where the initial velocity initial is zero, and I used a model with external force term. At the case 2D, my simulation woked with U_ {LB} 0.02, but at the case 3D this value does not work. I changed this value for 0.3.

The choice of these values ​​was to see the examples of the website of Palabos.

But at this moment I still can not explain why it is necessary to make that change.

Can someone tell me the reason, or where can I find literature about this topic?

Thanks for your help