The initial stage of fretting fatigue crack growth is significantly influenced by tangential force induced by fretting action along the contact surface where a mixed-mode crack growth is involved. Fretting crack behavior of aluminum alloy 2024 was studied, taking into account the problem of contact asperities. Finite element was used for the determination of the stress field near the contact su...

Adaptive morphing trailing edge wings have the potential to reduce the fuel burn of transport aircraft. In this paper, we quantify the aerodynamic performance benefits of a morphing trailing using aerodynamic design optimization. The aerodynamic model solves the Reynolds-averaged Navier– Stokes equations with a Spalart–Allmaras turbulence model. A gradient-based optimization algorithm is used i...

-Two sets of higher order equivalent edge currents are introduced which, in combination, account for the first-, the second-, and part of the third-order edge diffraction caused by the fringe wave surface current induced on a perfectly conducting polygonal plate in a radar scattering configuration. The first set represents the fringe wave surface current excited by the incident plane wave at th...

When the sinusoidal grating of a "Gabor pattern" is drifted, the apparent position of the pattern shifts in the direction of motion [De Valois, R. L., & De Valois, K. K. (1991). Vernier acuity with stationary moving Gabors. Vision Research, 31, 1619-1626]. We investigated the underlying cause of this illusion by determining whether the effect is a consequence of the internal motion shifting the...

Direct numerical simulationhas been carried out for turbulent  owovera rectangular trailing edge at aReynolds number of 1 £ £ 103 (based on the freestream quantities and the trailing-edge thickness) and ratio of boundarylayer displacement thickness to trailing-edge thickness close to unity. Two types of  ow control were studied: base transpiration and secondary splitter plate. Simulation of b...

Flatback airfoils are with a blunt trailing edge. They currently commonly used in the inboard part of large wind turbine blades, as they offer number aerodynamic, structural, and aeroelastic benefits. However, flow past them at high angles attack (AoA) has received relatively little attention until now. This is important because usually operate AoA Wind Turbine blades. The present investigation...

We have used computational fluid dynamics to study changes in lift generation and vortex dynamics for Reynolds numbers (Re) between 8 and 128. The immersed boundary method was used to model a two-dimensional wing through one stroke cycle. We calculated lift and drag coefficients as a function of time and related changes in lift to the shedding or attachment of the leading and trailing edge vort...