Numerical simulations of a two-dimensional airfoil, controlled by an applied moment in pitch and an airfoil controlled by jets, were investigated. These simulations couple the Reynolds-averaged Navier-Stokes equations and Euler's equations of rigid body motion, with an active control system. Controllers for both systems were designed to track altitude commands and were evaluated by simulating a...

Abstract In the current study, mid cross section of dragonfly forewing was simulated at ultra-low Reynolds number. The study aims to understand better contribution corrugations found along wing on aerodynamic performance during a forward flight. Different flapping parameters were employed. FLUENT solver used solve unsteady, two-dimensional, laminar, incompressible Navier–Stokes equations. resul...

This article presents application of an adjoint method to the aerodynamic shape optimization of deflector vanes installed in the fan nozzle of a turbofan engine. The purpose of the vanes is to reduce jet noise radiated towards the community, and the specific application of this study is for a supersonic turbofan engines with bypass ratio 2.7. The cost function used in the optimization includes ...

The unsteady wake of an EPPLER 361 airfoil in pitching motion has been investigated in a subsonic wind tunnel by hot-wire anemometry. The airfoil was given the pitching motion about the one-quarter chord axis at reduced frequency of 0182. Streamwise mean velocity profiles (wake profiles) were investigated at several vertically aligned points behind the airfoil at one-quarter chord downstream di...

Two-dimensional direct numerical simulation of the flow over a NACA0018 airfoil with a cavity is presented. The lowReynolds number simulations are validated bymeans of flow visualizations carried out in awater channel. From the simulations, it follows that there are twomain regimes of flow inside the cavity. Depending on the angle of attack, the first or the second shear-layer mode (Rossiter to...

A t the impact of a plunging liquid jet with a receiving pool, air bubbles may be entrained if the impact velocity exceeds a critical velocity. New experiments were performed in a two-dimensional plunging jet. The ̄ ow conditions near the inception of air entrainment were investigated. Two mechanisms of air entrainment were visualized at low jet velocities: by elongated air cavity and by foam bu...

Based on Navier-Stokes equations and structural and flight dynamic equations of motion, dynamic responses in vertical discrete gust flow perturbation are investigated for a supersonic transport model. A tightly coupled method was developed by the subiteration between aerodynamic equations and dynamic equations of motion. First, under the assumption of rigid-body and single freedom of motion in ...

Laboratory experiment is conducted to investigate the long waves generated by time-varying breakpoint. We focus our attention on the variation of plunging point as well as the variation of breaking point. The results show that free long waves (BFLW) are really generated by the variation of the starting point of wave set-up which coincide with the plunging point and that the BFLW observed can be...

This paper concerns a numerical study of employing an adaptive trailing edge flap to control the lift of an airfoil subject to unsteady inflow conditions. The periodically varying inflow is generated by two oscillating airfoils, which are located upstream of the controlled airfoil. To establish the control system, a standard PID controller is implemented in a finite volume based incompressible ...