Hypersonic rareŽ ed-gas  ows near two side-by-side plates have been studied numerically with the direct simulationMonte Carlo technique under transitional rareŽ ed-gas- ow conditions (Knudsen numbers from 0.024 to 1.8). Strong in uences of the geometrical factor (ratio of distance between plates to plate length) and the Knudsen number on the  ow structure (the shape of shock waves, the conŽ...

To improve the low aerodynamic efficiency and reduce high energy consumption of a single-stage circulation control wing, multistage wing was designed. By combining force measurement particle image velocimetry (PIV), flow-field characteristics an aerofoil were investigated with respect to increase in number blowing slots, changes coefficient, different ratios for three slots. The results reveale...

Ax, A = amplitude of stroke amplitude in x direction, m, and orientation angle, deg CL, CL = lift coefficient and its average over flapping cycles CD, CD = drag coefficient and its average over flapping cycles CPW, CPW = input power coefficient and its average over flapping cycles c, h = chord and thickness of the plate, m; c is chosen as characteristic length Re = Uc v , Reynolds number, v is ...

Bird flight is an area of significant interest due to the utilization and control of unsteady aerodynamic effects via flapping. Although modern aerodynamics were originally inspired by bird flight, contemporary computational and experimental work associated with flapping flight focuses on insect flight. The purpose of the present paper is to improve the understanding of avian flight by investig...

The Breguet range equation indicates that to the first order of approximation range will be maximized by maximizing ML/D, where M is the Mach number and L/D is the lift/drag ratio. Since the drag coefficient increases very rapidly as the Mach number approaches one, this leads to the design of a long range aircraft which fly at high subsonic speeds, typically in the range Mach 0.8 to 0.85, just ...

Studies of insect flight have focused on aerodynamic lift, both in quasi-steady and unsteady regimes. This is partly influenced by the choice of hovering motions along a horizontal stroke plane, where aerodynamic drag makes no contribution to the vertical force. In contrast, some of the best hoverers--dragonflies and hoverflies--employ inclined stroke planes, where the drag in the down- and ups...

The flying fish (family Exocoetidae) is an exceptional marine flying vertebrate, utilizing the advantages of moving in two different media, i.e. swimming in water and flying in air. Despite some physical limitations by moving in both water and air, the flying fish has evolved to have good aerodynamic designs (such as the hypertrophied fins and cylindrical body with a ventrally flattened surface...

The aim of this paper is to determine the hydrodynamic characteristics of swimmer's scanned hand models for various combinations of both the angle of attack and the sweepback angle and shape and velocity of swimmer's hand, simulating separate underwater arm stroke phases of freestyle (front crawl) swimming. Four realistic 3D models of swimmer's hand corresponding to different combinations of se...

This paper studies several problems that may exist in the aerodynamic design of low Mach number general aircraft, and discusses characteristics pressure distribution some related airfoils while part is verified by a multi-point laminar airfoil case. Firstly, issues which such as relatively large zero-lift drag coefficient, high stall performance requirements, variation range Reynolds number, ar...

in many industrial equipment such as boilers and heat exchangers, the cylindrical tubes are exposed to the gas- liquid two phase flow. for any immersed body in flow field vortex shedding is created with a frequency that may be constant or variable, according to conditions such as flow rates, geometry of body, and etc. the failure will happen in the equipment, when this frequency is close to one...