RANDOM WALK SOURCE MODEL AND LIFT COEFFICIENT

Abstract

The author extends his numerical method for obtaining the lift coefficient of wing sections which bases on a random-walk algorithm. In the former paper [2] the phenomenon of migrating fluid fronts in filter paper around macroscopic obstacles lead to a numerical model of unsteady potential flow the author calls "random walk source model." The shape of the migrating fluid fronts simulated in the random walk model tells the history of the path of fluid particles on their way to the front; it, thus, carries the information about the lift coefficient of the passed wing section. He now studies the path of the center of gravity of the "cloud" of migrating simulated fluid particles around Joukowsky profiles whose lift coefficient is known, and compares the theoretical lift coefficient with the numerically determined value of path deflection of the center of gravity, resulting from the random walk experiment. The theoretical discussion of the path deflection leads to a formula which predicts the mafmum of possible lift coefficient one can obtain with circulation around wing sections in ideal fluids.