An isogeometric boundary element method for three-dimensional lifting flows

Student thesis: Doctoral Thesis

Abstract

In this PhD thesis an Isogeometric Boundary Element Method (IGA-BEM) for three dimensional steady lifting flows based on Morino's [50] formulation is presented. A potential flow assumption is used and the unknown perturbation potential satisfies Laplace's equation. Application of Green's identities leads to a Boundary Integral Equation (BIE) that is enhanced with kinematic and dynamic boundary conditions.Analysis suitable T-splines are used for the representation of all boundary surfaces and the unknown perturbation potential is approximated by the same T-spline basis as the one used for the geometry. The BIE is discretised by enforcing it on the generalised version of Greville points for unstructured T-meshes. A novel numerical application of the so-called Kutta condition is introduced that utilises the advantages of IGA with regard to the smoothness of the trailing edge curve basis functions.This leads to a quadratic system that is solved by a Newton-Raphson iterative scheme. The method is applied for three different test cases and shows good agreement with existing experimental results and superior behaviour when compared to a low order panel method.The effect of the tip singularity on Kutta condition is also investigated for different levels of refinement and positions of the trailing edge collocation points.
Date of Award25 Nov 2020
Original languageEnglish
Awarding Institution
  • University Of Strathclyde
SupervisorPanagiotis Kaklis (Supervisor) & Qing Xiao (Supervisor)

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