The formation of the tip-vortex from a rectangular NACA 2415 wing-tip at a chord Reynolds number of 10000 has been simulated. The simulations employ a parallelized compressible large-eddy simulation (LES) solver that has been developed to simulate wing and rotor tip-flows. The solver employs an immersed-boundary technique in conjunction with a curvilinear structured grid and the dynamic model i...

In this study, the aerodynamic sound generated from the inclined circular cylinder was investigated experimentally and numerically. The generated sound and a coherent length of velocity fluctuation along the cylinder axis were measured by a low-noise wind tunnel with endplates. The sound and the flow in wake were also simulated by Large Eddy Simulation and Lighthill-Curle’s equation. We got the...

A finite-difference machine code is brought to bear on the wake-vortex problem in the quasi-cylindrical boundary-layer approximation. A turbulent-energy model containing new features is developed that accounts for the major effects disclosed by more advanced models in which the parameters are not yet established. Several puzzles are resolved that arose in previous theoretical investigations of ...

When a cylindrical tool cuts through a thin sheet of a relatively brittle material, it leaves behind a visually arresting crack street in its wake, reminiscent of a vortex street in the wake of a cylinder moving through a fluid. We show that simple geometrical arguments based on the interplay of in-plane stretching and out-of-plane bending suffice to explain the cycloidal morphology of the curv...

Koi carps frequently swim in burst-and-coast style, which consists of a burst phase and a coast phase. We quantify the swimming kinematics and the flow patterns generated by the carps in burst-and-coast swimming. In the burst phase, the carps burst in two modes: in the first, the tail beats for at least one cycle (multiple tail-beat mode); in the second, the tail beats for only a half-cycle (ha...