The flow mechanism leading to the enhanced performance of a discrete co-flow jet (dCFJ) airfoil is investigated. Flow visualization and DPIV are used to analyze the difference between the flow along discrete jets and over the tabs used for discretization of the slot jet. Results show that the entrainment is uniform over the leading jet as long as the tab size is small enough. The jets expand sp...

In this contribution, the unsteady, viscous and two dimensional flow over a plunging NACA0012 airfoil was simulated using a high-order numerical method associated with a moving frame of reference technique. The goal of using a high-order numerical method is to characterize heaving airfoil wakes with very fine temporal and spatial resolutions. This characterization is essential in understanding ...

The problem investigated in this experiment was which height of Gurney Flap gives the best lift improvement on an airfoil without increasing drag. The Gurney Flaps' heights are determined as a percentage of the airfoil's chord length. The hypothesis is that a Gurney Flap will produce the best lift to drag ratio when its height is two percent of the airfoil's chord length. The hypothesis was tes...

The vertex-edge Wiener polynomials of a simple connected graph are defined based on the distances between vertices and edges of that graph. The first derivative of these polynomials at one are called the vertex-edge Wiener indices. In this paper, we express some basic properties of the first and second vertex-edge Wiener polynomials of simple connected graphs and compare the first and second ve...

in this paper, inflow turbulence effects on the flow wake parameters around a naca0012 airfoil at zero incidence angle and reynolds number of 38,700 were investigated. various turbulence promoter networks were used to achieve turbulence intensity of 5% and 6%. experiments have been conducted for three different turbulence intensities in which mean velocity parameters, turbulence intensity, freq...

Under the right parameters, flutter occurs in an airfoil when aerodynamic forces drive a dynamic structure to an oscillatory, possibly divergent condition. The presence of a rotational stiffness nonlinearity at the root of an all-moving airfoil has been shown to decrease the freestream velocity at which flutter occurs. Since this is a somewhat common configuration for flight structures and othe...

Direct numerical simulations were performed to study the effect of an elastically mounted trailing edge actuator on the unsteady flow over a plunging, thin airfoil at Reynolds number of 14700 based on the chord length. The goal is to investigate potential benefits of flow-induced passive actuation of the trailing edge to the lift and drag characteristics of flapping MAV wings. The trailing edge...

In this study, efficient global optimization (EGO) with a multi-fidelity hybrid surrogate model for multi-objective optimization is proposed to solve multi-objective real-world design problems. In the proposed approach, a design exploration is carried out assisted by surrogate models, which are constructed by adding a local deviation estimated by the kriging method and a global model approximat...

A NUMBER of military and civilian applications require efficient operation of airfoils in low chord Reynolds numbers. The applications include propellers, sailplanes, ultralight mancarrying/man-powered aircraft, high-altitude vehicles, wind turbines, unmanned aerial vehicles, and micro air vehicles. Careful management of boundary layers on low-Reynolds-number airfoils is required to alleviate t...