Abstract
The results of experimental investigations of the unsteady motion of various bodies are presented. The drag of a disk, sphere, and various axisymmetric bodies under accelerated motion from a state of rest under various laws of a change in the velocity of motion is investigated. The experiments were performed at various experimental installations. The dependences of the drag force on the speed of motion and the coefficient of nonstationary drag of poorly streamlined bodies on dimensionless acceleration and the coefficient of nonstationary resistance during accelerated movement from a state of rest depending on the Reynolds number and acceleration number are given. The effect of nonstationarity on the mechanism of drag formation is experimentally and theoretically investigated. The experiments were performed on a body of revolution with an elongation of 7.15 under the three laws of nonstationarity. The energy aspects of the motion of bodies in various modes of acceleration and braking are experimentally investigated. It is shown that the nonstationary mode of motion, consisting of alternating periods of acceleration and deceleration, may be more preferable in comparison with the stationary mode of motion. Photographs of the visualization of the flow around various canonical bodies during unsteady motion, in particular, when controlling separated flow, are given.
Published Version
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