sahar noori; Ava Shahrokhi
Volume 8, Issue 2 , September 2011, , Pages 127-133
Abstract
To improve the calculation of the flow properties of an aerospike nozzle, different turbulence models were investigated in this study. The primary shape of the nozzle plug is determined through utilizing an approximate method. The flow field is, then, simulated using the Navier-Stokes equations for compressible ...
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To improve the calculation of the flow properties of an aerospike nozzle, different turbulence models were investigated in this study. The primary shape of the nozzle plug is determined through utilizing an approximate method. The flow field is, then, simulated using the Navier-Stokes equations for compressible flows. The commercial computational fluid dynamics code Fluent is used to simulate the flow around an aerospike nozzle. The computational methodology employs steady state density-based formulation and a finite volume cell centered scheme to discretize the flow field equations. To accelerate the solution convergence, the flow field is divided into several zones in order to facilitate each zone with proper unstructured grid and also to offer the appropriate initial conditions for each zone. The accuracy and the robustness of wall function based turbulence schemes, i.e. k-e model, are compared with those of Spalart-Allmaras (S-A) and k-? turbulence models.
Ava Shahrokhi; Alireza Jahangirian
Volume 5, Issue 1 , March 2008, , Pages 35-43
Abstract
The effect of airfoil shape parameterization on optimum design and its influence on the convergence of the evolutionary optimization process is presented. Three popular airfoil parametric methods including PARSEC, Sobieczky and B-Spline (Bezier curve) are studied and their efficiency and results are ...
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The effect of airfoil shape parameterization on optimum design and its influence on the convergence of the evolutionary optimization process is presented. Three popular airfoil parametric methods including PARSEC, Sobieczky and B-Spline (Bezier curve) are studied and their efficiency and results are compared with those of a new method. The new method takes into consideration the characteristics of viscous transonic flows particularly around the trailing edge. The methods are applied to airfoil shape optimization at high Reynolds number turbulent flow conditions using Genetic Algorithm. An unstructured grid Navier-Stokes flow solver with a two-equation K-e turbulence model is used to evaluate the objective function. The original mesh movement strategy (Spring analogy) is modified particularly inside the boundary layer in order to maintain the quality of cells in this area. The aerodynamic characteristics of the optimum airfoil obtained from the proposed parametric method are compared with those from alternative methods. It is concluded that the new method is capable of finding efficient and optimum airfoils in fewer number of evaluations.
