Again, as we have seen that, so what will happen at the bottom? Also, if I just consider this as this is my, then this is my y is equal to 0 my still water level. I think of water of uniform depth. This is y is equal to minus h. Then, what will happen? Here, we have Laplace equation delta phi 0 and at the bottom, we have phi y is 0. This is on y is minus h. Here, I have phi t, t plus g phi y is 0. This is on y is equal to 0. So, this becomes, the governing equation is Laplace equation. We have 2 conditions; one is the mean free surface. We have phi t, t plus phi y 0. At the bottom boundary, we have y is equal to minus h. Here, we have phi is equal to 0.