In the present study, multi-objective optimization of 4-digit NACA airfoils is performed at three steps. At the first step, lift (CL) and drag (CD) coefficient in a set of 4-digit NACA airfoils are numerically investigated using commercial software NUMECA. Two meta-models based on the evolved Group Method of Data Handling (GMDH) type neural networks are obtained, at the second step, for modelin...

in this paper, lift and drag coefficients were numerically investigated using numeca software in a set of 4-digit naca airfoils. two metamodels based on the evolved group method of data handling (gmdh) type neural networks were then obtained for modeling both lift coefficient (cl) and drag coefficient (cd) with respect to the geometrical design parameters. after using such obtained polynomial n...

In this paper, lift and drag coefficients were numerically investigated using NUMECA software in a set of 4-digit NACA airfoils. Two metamodels based on the evolved group method of data handling (GMDH) type neural networks were then obtained for modeling both lift coefficient (CL) and drag coefficient (CD) with respect to the geometrical design parameters. After using such obtained polynomial n...

A high order spectral difference (SD) scheme based cost-effective multi-level optimization approach is proposed to optimize the kinematics of flapping airfoils and provide further insights into flapping motions with maximum propulsive efficiency. At the first stage, a gradient-based optimization algorithm is coupled with a second-order SD Navier-Stokes solver to search for the optimal kinematic...

The equations for the NACA 4-digit and 4-digitmodified sections are in algebraic form and easily incorporated into various geometrical procedures that define a vehicle and any necessary flow field grid. The 6-series and 6A-series airfoils are more complex because they are developed by conformal mapping procedures. Even though there are computer programs available (refs 1-3) that can produce a l...

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...

Multiple numerical solutions of inviscid transonic flow over several airfoils exist at certain Mach number and angle of attack. Global linear stability analysis of the multiple solutions is conducted in this paper. Linear perturbation equations of the Euler equations around a steady-state solution are formed, an eigenvalue problem is then constructed using the modal analysis approach, then it i...

Abstract―This paper illustrates the theory behind computational fluid dynamics (CFD) of flow though a gas turbine engine low pressure compressor. The goal of study is to develop a tool to perform shape optimization of low speed airfoils. Mathematical model and computational tool are developed using programming software. Analytical solution is developed to create airfoil geometry. The NACA 4 dig...