The gravity potential is the scalar potential, the gravitational potential energy per unit mass. Fluid dynamics have a scalar potential in the special case. Certain aspects of the nuclear force be described by a Yukawa potential. Examples of non-conservative forces include frictional forces, magnetic forces in a solenoidal field velocity field in fluid mechanics. Gravitational potential energy is proportional to altitude. The hilly region represented by the three-dimensional negative gradient of U by the contour map.
Fluid mechanics is permeated by a uniform buoyant force. This buoyant force is the negative gradient of pressure. Pressure increases below the surface of the water to the depth. The surfaces of constant pressure are parallel planes to the surface.