Path optimization of flapping airfoils based on unsteady viscous flow solutions

Download

index.pdf

Date

2008

Author

Kaya, Mustafa

Metadata

Show full item record

Item Usage Stats

214
views

288
downloads

The flapping path of a single airfoil and dual airfoils in a biplane configuration is optimized for maximum thrust and/or propulsive efficiency. Unsteady, low speed viscous flows are computed using a Navier-Stokes solver in a parallel computing environment. A gradient based algorithm and Response Surface Methodology (RSM) are employed for optimization. The evaluation of gradient vector components and the design of experiments for RSM, which require unsteady solutions, are also carried out in parallel. Parallel computations are performed using Parallel Virtual Machine (PVM) library. First, a single airfoil undergoing a combined sinusoidal or non-sinusoidal pitching and plunging motion is studied. The non-sinusoidal flapping motion is described using an elliptic curve or Non-Uniform Rational B-Splines (NURBS). It is shown that the thrust generation may significantly be increased in comparison to the sinusoidal flapping motion. For a high thrust, the airfoil stays at high effective angle of attack values during the upstroke and the downstroke, and the effective pitching occurs at minimum and maximum plunge positions. Secondly, the optimization of sinusoidal and non-sinusoidal flapping paths of dual airfoils is considered. Moving and deforming overset grids are used for computations. The deforming overset grids remove the restrictions on the flapping motion, and improve the optimization results obtained earlier. At low flapping frequencies, an airfoil in a biplane configuration produces more thrust than a single airfoil. Yet, at high frequencies the airfoil in biplane configuration produces less thrust at a significantly lower efficiency than the single airfoil.

Subject Keywords

Aeronautics., Astronautics.

URI

http://etd.lib.metu.edu.tr/upload/2/12609349/index.pdf
https://hdl.handle.net/11511/17596

Collections

Graduate School of Natural and Applied Sciences, Thesis

Suggestions

OpenMETU
Core

Path optimization of dual airfoils flapping in a biplane configuration with RSM in a parallel computing environment Kaya, Mustafa; Tuncer, İsmail Hakkı (2011-01-01) The path of dual airfoils in a biplane configuration undergoing a combined, non-sinusoidal pitching and plunging motion is optimized for maximum thrust and/or propulsive efficiency. The non-sinusoidal, periodic flapping motion is described using Non-Uniform Rational B-Splines (NURBS). The Response Surface Methodology (RSM) is employed for the optimization of NURBS parameters in a parallel computing environment. A gradient based optimization algorithm, steepest ascent method is started from the optimum point...
Optimization of Flapping Motion Parameters for Two Airfoils in a Biplane Configuration Kaya, Mustafa; Tuncer, İsmail Hakkı; Jones, Kevin D.; Platzer, Max F. (American Institute of Aeronautics and Astronautics (AIAA), 2009-03-01) Flapping motion parameters of airfoils in a biplane configuration are optimized for maximum thrust and/or propulsive efficiency. Unsteady, viscous flowfields over airfoils flapping in a combined plunge and pitch are computed with a parallel flow solver on moving and deforming overset grids. The amplitudes of the sinusoidal pitch and plunge motions and the phase shift between them are optimized for a range of flapping frequencies. A gradient-based optimization algorithm is implemented in a parallel computing...
Parallel optimization of flapping airfoils in a biplane configuration for maximum thrust Tuncer, İsmail Hakkı (2004-05-27) Flapping airfoils in a biplane configuration are optimized for a maximum thrust production. A parallel Navier-Stokes solver on overset grids and a gradient based parallel optimization method are employed. The periodic flapping motion of airfoils in a plane configuration is described in a combined pitch and plunge. The pitch and plunge amplitudes and the phase shift between them are optimized for a range of flapping frequencies. It is shown that at low flapping frequencies, flapping airfoils in a biplane con...
Non-sinusoidal path optimization of dual airfoils flapping in a biplane configuration KAYA, MUHAMMED ÇAĞRI; Tuncer, İsmail Hakkı (2009-10-12) The path of dual airfoils in a biplane configuration undergoing a combined, non-sinusoidal pitching and plunging motion is optimized for maximum thrust and/or propulsive efficiency. The non-sinusoidal, periodic flapping motion is described using Non-Uniform Rational B-Splines (NURBS). A gradient based algorithm is then employed for the optimization of the NURBS parameters. Unsteady, low speed laminar flows are computed using a Navier-Stokes solver in a parallel computing environment based on domain decompos...
Optimization of flapping motion of airfoils in biplane configuration for maximum thrust and/or efficiency Kaya, Mustafa; Tuncer, İsmail Hakkı; Jones, Kevin D.; Platzer, Max F. (2007-01-01) Flapping motion of airfoils in a biplane configuration are optimized for maximizing the thrust and propulsive efficiency. Unsteady flowfields over airfoils flapping in a combined plunge and pitch are computed with a parallel viscous flow solver on moving and deforming overset grids. The amplitudes of the sinusoidal pitch and plunge motions and the phase shift between them are optimized at a fixed flapping frequency and average distance between two airfoils. A gradient based optimization algorithm is impleme...

Citation Formats

M. Kaya, “Path optimization of flapping airfoils based on unsteady viscous flow solutions,” Ph.D. - Doctoral Program, Middle East Technical University, 2008.