Author: J. E. YatesPublisher:
ISBN: 9789283513063
Category : Aerodynamic load
Languages : en
Pages : 18
Book Description
Unsteady Viscous Thin Airfoil Theory
Author: J. E. YatesPublisher:
ISBN: 9789283513063
Category : Aerodynamic load
Languages : en
Pages : 18
Book Description
Viscous Thin Airfoil Theory
Author: John E. YatesPublisher:
ISBN:
Category :
Languages : en
Pages : 65
Book Description
The theory of oscillating thin airfoils in incompressible viscous flow is formulated and applied to the calculation of steady and unsteady loads on the family of symmetric Joukowski airfoils. The theory is reduced to the form of an integral equation with kernel function whose solution is obtained with a modal expansion technique familiar from flat plate thin airfoil theory. The effect of viscosity is to change the order of the singularity in the kernel function such that a unique solution is obtained for any cross sectional geometry without using an auxiliary uniqueness criteria like the Kutta condition or principle of minimum singularity. Viscous thin airfoil calculations for an airfoil with sharp trailing edge are in agreement with the results of potential theory with Kutta condition. Viscous thin airfoil steady and unsteady calculations for an airfoil with elliptic cross section are in much better agreement with experimental results. It is concluded that viscous thin airfoil theory is a practical tool for introducing simultaneously the effects of viscosity and geometric thickness in two-dimensional unsteady aerodynamic theory.
On the Singular Role of Viscosity in the Theory of Thin Airfoils
Author: John E. YatesPublisher:
ISBN:
Category :
Languages : en
Pages : 53
Book Description
The general problem of a lifting incompressible viscous thin airfoil is formulated and the viscous counterpart of the classical thin airfoil equation is derived. For any Reynolds number, however large, it is shown that the Cauchy singularity in the kernel is replaced by a logarithmic singularity and the resulting kernel does not have upstream/downstream symmetry. The downstream influence decays algebraically, while upstream influence decays exponentially with distance away from the singularity. A moment solution of the viscous airfoil equation is developed in the limit of high Reynolds number. The classical steady state 'Kutta Condition' is derived in the limit and the Reynolds number correction is found to be of order (1/1n Re), much greater than inviscid boundary layer thickness effects. For Reynolds numbers between one and ten million there is a 20% reduction in the lift curve slope that offsets the increase due to geometric thickness. The correction correlates reasonably well with experiment for a large variety of thin airfoils. The unsteady viscous thin airfoil equation is derived and the singularities of the kernel are discussed in the light of recent experimental work on oscillating airfoils.
A Unified Viscous Theory of Lift and Drag of 2-D Thin Airfoils and 3-D Thin Wings
Author: John E. YatesPublisher:
ISBN:
Category : Aerodynamic load
Languages : en
Pages : 104
Book Description
Scientific and Technical Aerospace Reports
Author: Fundamentals of Modern Unsteady Aerodynamics
Author: Ülgen GülçatPublisher: Springer
ISBN: 9811000182
Category : Technology & Engineering
Languages : en
Pages : 402
Book Description
In this book, the author introduces the concept of unsteady aerodynamics and its underlying principles. He provides the readers with a comprehensive review of the fundamental physics of free and forced unsteadiness, the terminology and basic equations of aerodynamics ranging from incompressible flow to hypersonics. The book also covers modern topics related to the developments made in recent years, especially in relation to wing flapping for propulsion. The book is written for graduate and senior year undergraduate students in aerodynamics and also serves as a reference for experienced researchers. Each chapter includes ample examples, questions, problems and relevant references. The treatment of these modern topics has been completely revised end expanded for the new edition. It now includes new numerical examples, a section on the ground effect, and state-space representation.
Turbomachine Unsteady Aerodynamics
Author: J. S. RaoPublisher: New Age International
ISBN: 9788122406535
Category : Science
Languages : en
Pages : 542
Book Description
Nonlinear Stability of Unsteady Viscous Flow
Author: Alric P. RothmayerPublisher:
ISBN:
Category : Boundary layer
Languages : en
Pages : 196
Book Description
Viscous Theory of Surface Noise Interaction Phenomena
Author: John E. YatesPublisher:
ISBN:
Category : Acoustic streaming
Languages : en
Pages : 50
Book Description
Author: