number is depending as the ratio of 2 forces. It is the ratio of inertia force to the pressure force. This Euler force is important particularly when there is gravitation. We all know that there is a region when you have seen that in case of the formation of cavity, when the pressure becomes negative, the cavity formation takes place and near in gravitational flows flows. This Euler number becomes very important, plays a significant role. It is a ratio of the ratio of the inertia force to pressure force in gravitational flows. The Euler number plays the significant role.