Aerodynamic force models for animating cloth motion in air flow

Abstract

This paper is focused on the analysis of the intersection between the air-flow field around a piece of cloth and the motion of the cloth in order to animate realistically the cloth motion in the air flow. Two force models, based on aerodynamic theory, have been established to calculate the force distribution of the air flow on a cloth surface. The quasi-steady force model deals with the cases in which the free stream velocity of the relative air flow changes slightly or slowly, whereas the unsteady force model deals with unsteady air flows. The resulting force distributions are coupled with a cloth-deformation model based on structural dynamics to compute the displacement and deformation of cloth under these forces. This solution cycle is repeated and the time histories of the cloth motion can be obtained which form the basis of the computer animation of cloth motion in air flow. Animation results of the movement of a piece of curtain in free air under various air flow conditions are presented to compare the performances of the two force models.