Impact of Gravity on Fluid Mechanics Models

Mathematical formulae which describe fluid mechanics models include the influence of gravity. In the literature and practice, when considering numerical hydraulic models, gravity is taken as constant value (“gravitational constant”). Actually, gravity is not constant and it is changing depending on mass distribution into the body of the Earth, mass density, altitude and topography (relief shape and mas density above the geoid). This paper is focused on the gravity influence on the different hydraulics models and fluid mechanic formulae in order to point out that gravity acceleration should not be treated routinely as “constant”.