As airplane designs have trended toward the expansion of flight envelopes into the high angle of attack and high angular rate regimes, concerns regarding modeling the complex unsteady aerodynamics for simulation have arisen. Most current modeling methods still rely on traditional body axis damping coefficients that are measured using techniques which were intended for relatively benign flight c...

The Unsteady Vortex-Lattice Method provides a medium-fidelity tool for the prediction of non-stationary aerodynamic loads in low-speed, but high-Reynolds-number, attached flow conditions. Despite a proven track record in applications where free-wake modelling is critical, other less-computationally-expensive potential-flow models, such as the Doublet-Lattice Method and strip theory, have long b...

A lightweight flapping-wing micro air vehicle (MAV) was designed and built and successfully filed in the sky. The unsteady aerodynamics associated with this MAV was detailedly studied by using the method of computational fluid dynamics (CFD).The variations of different parameters of the flapping MAV, such as flapping amplitude, pitch amplitude and flapping frequency, were investigated with nume...

A collection of computational fluid dynamics tools and techniques are being developed and tested for application to stage separation and abort simulation for next-generation launch vehicles. In this work, an overset grid Navier-Stokes flow solver has been enhanced and demonstrated on a matrix of proximity cases and on a dynamic separation simulation of a belly-to-belly wing-body configuration. ...

Aerodynamic drag reduction is required with new stringent constraints on pollutant emissions and fuel efficiency of ground vehicles. In this context, active flow control a promising approach to achieve target. This study focuses applying different strategies the square-back Ahmed model reduce aerodynamic drag. A steady blowing jet, synthetic jet an unsteady are located at back edges as devices....

in the present paper, the aeroelastic stability of helicopter rotor blade is determined using aeroelastic frequency response function. the aeroelastic model of blade is obtained by combining dowell - hodges beam model with loewy unsteady aerodynamic theory which considers an unsteady wake beneath the rotor. equations are formed and aeroelastic frequency response functions are obtained by invert...

The blades of wind turbines are the most important parts in producing power output. In this study, a section of a 660 KW wind turbine blade will be installed in Iran in near future was tested in a wind tunnel. In addition to steady tests, various unsteady tests including the effects of reduced frequency, mean angle of attack, and amplitudes were carried out. The preliminary results show strong ...

The aerodynamic noise and vibration caused by the vehicle door mirror has been much studied [1], largely by numerical simulation [2]. It is evident that the aerodynamic noise and vibration are strongly associated with the flow structures, and the unsteady behavior of the vortex causes the wind noise. Recently the aero-acoustic characteristics of a vehicle door mirror were also studied by numeri...

Unsteady dynamic behavior of TTCP model with different wrap around fin sets were investigated in a trisonic wind tunne. The aerodynamic coefficient force measurement in this wind tunnel shows good agreement in comparison with that of the NASA Langley Research Center in static case. The model was sinusoidally oscillated at three different frequencies of 1, 3 and 8 Hz at M=2.0 and the effects of ...

Supersonic flow over a capsule-shaped abort system with angle of attack (AoA) of α, which is boosted by supersonic aerodynamic interference, is investigated numerically through the 3D simulation. The objective of this study is to examine the effects of AoA on aerodynamic stability. In the previous study, the flowfield around this system at α = 0 is unsteady and has a strong periodic flow oscill...