QUANTITATIVE-EVALUATION OF EFFECT OF GRAVITY ON SMALL-SCALE MODELING

In many cases, small-scale modeling requires the scaling up of the gra vitational acceleration. Yet this requirement sets a technical problem , and unless the use of a centrifuge is available, it is not fulfilled . Consequently there is a distortion in the extrapolated results of th e small-scale model, which lacks scaling of gravity. So far, the exten t of the effect of gravity scaling on the extrapolated results has bee n speculated. A quantitative way to evaluate this effect is suggested here. An expression for the distortion in the extrapolation of a measu red model variable is developed, based on similitude requirements. Thi s expression depends on the geometrical scaling factor, and on the rat io of a variable measured model value to the value of its gravitationa l component. It shows that for geometrical scling factors of 10 and 50 , the distortion is less than 10% when the gravitational component of the variable is less than 1% and approximately 0.2%, respectively.