Reply To: two interraction body in AQWA

[Shuangxing Du]

Please check all the force components (such as, Froude-Krylov force, hydrostatic force,  etc) in z direction.  One or more force components may not be right in your model.  From z-poistion time history, within the starting one second time, the piston drops down by 5 meters, which may mean that the piston motion is mainly freely falling due to the gravity force, the hydrostatic force is either small or in the wrong direction.  If the hydrostatic force is either small or in the wrong direction, please check the surface normal direction of the piston. Aqwa requires all the surfaces'normal directions point towards external fluid region.