CST method is a powerful parameterization method because of its simplicity, robustness, and its ability to be generalized into various possible shapes of aerodynamic bodies. The geometry from CST itself is mainly determined by the formula of class and shape function. Application of CST to transonic airfoil optimization is still rare and more studies are needed. This work studies the application...

To control the Karman vortex street formed behind a thin airfoil at a certain incidence, a control cylinder was placed at the suction side apart from the airfoil in the downstream region. Both smoke visualization and hot-wire measurements confirmed that the Karman vortex street was completely suppressed. The mechanism for suppression of the vortex street was examined with a hot-wire survey.

Increasing the combustion temperatures in a gas turbine engine to achieve higher efficiency and power output also results in high heat loads to turbine components downstream of the combustor. The challenge of adequately cooling the nozzle guide vane directly downstream of the combustor is compounded by a complex vortical secondary flow at the junction of the endwall and the airfoil. This flow t...

Flow and turbulence models applied to the problem of shock bu et onset are studied. The accuracy of the interactive boundary layer and the thin-layer Navier-Stokes equations solved with recent upwind techniques using similar transport eld equation turbulence models is assessed for standard steady test cases, including conditions having signi cant shock separation. The two methods are found to c...

Direct numerical simulations (DNS) of flow over an NACA-0012 airfoil are performed at a low and a moderate Reynolds numbers of Rec=50*10 and 1*10. The angles of attack are 5 and 15 degrees at the low and the moderate Reynolds number cases respectively. The three-dimensional unsteady compressible Navier-Stokes equations are solved using higher order compact schemes. The flow field in the low Rey...

This paper demonstrates a new performance enhancement methodology for Co-Flow Jet (CFJ) airfoils using discrete injection jets. This research is motivated by the hypothesis that a discrete CFJ (DCFJ) airfoil will generate both streamwise and spanwise vortex structures to achieve more effective turbulent mixing than an open slot CFJ airfoil. Aerodynamic forces and DPIV measurements show that the...

High-fidelity numerical simulations with the spectral difference (SD) method are carried out to investigate the unsteady flow over a series of oscillating NACA 4-digit airfoils. Airfoil thickness and kinematics effects on the flapping airfoil propulsion are highlighted. It is confirmed that the aerodynamic performance of airfoils with different thickness can be very different under the same kin...

This paper applies a Reinforcement Learning methodology to the problem of airfoil morphing. The reinforcement learning as it is applied to morphing is integrated with a computational model of an airfoil. The computational model utilizes a doublet panel method whose end yield is airfoil lift, drag, and moment coefficients. An episodic unsupervised learning simulation using the Q-Learning method ...

An experimental study was conducted to investigate the aerodynamic characteristics of a bio-inspired corrugated airfoil compared with a streamlined airfoil and a flat plate at the chord Reynolds number of Re= 58,000 ~ 125,000 to explore the potential applications of such bio-inspired corrugated airfoils for micro air vehicle (MAV) designs. In addition to measuring the aerodynamic lift and drag ...

An implicit, Navier-Stokes solution algorithm is presented for the computation of turbulent flow on unstructured grids. The inviscid fluxes are computed using an upwind algorithm and the solution is advanced in time using a backward-Euler time-stepping scheme. At each time step, the linear system of equations is approximately solved with a point-implicit relaxation scheme. This methodology prov...