Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 31 for “"dynamic stall"”.
-
Unsteady flow physics of airfoil dynamic stall
… with the flow perturbations, for a canonical dynamic stall process. A series of unsteady surface pressure measurements, with a high sampling frequency, were acquired in order to investigate the time-dependent behavior of the flow in the immediate vicinity of the airfoil. These surface pressure …
-
Dynamic stall of a NACA 0012 airfoil in laminar flow
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1994.
-
Influence of aspect ratio on dynamic stall of a finite wing
… of aspect ratio, AR, on the unsteady aerodynamics of pitching wings was examined by comparing experimental performance, flow measurements, and computational results across a range of different AR wings. Performance measurements were acquired for three wings of AR = 3, 4, 5, and an airfoil …
-
Numerical simulation of dynamic stall for heaving airfoils using adaptive mesh techniques
In dieser Arbeit führen wir numerische Simulationen von Strömungen über absenkenden Flügelprofilen mit einer hochauflösenden Spektralen Elemente Methode durch. Es wird eine sehr detaillierte räumliche und zeitliche Beschreibung der Strömung erreicht. Die Ergebnisse, die wir bekommen haben sind mit …
-
An Airloads Theory for Morphing Airfoils in Dynamic Stall with Experimental Correlation
Helicopter rotor blades frequently encounter dynamic stall during normal flight conditions, limiting the applicability of classical thin-airfoil theory at large angles of attack. Also, it is evident that because of the largely different conditions on the advancing and retreating sides of the rotor, …
-
Spatio-temporal localization of canonical dynamic stall flow scales across varying Reynolds numbers
Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2027-08-01
-
Forecasting the lift of a randomly maneuvering airfoil under dynamic stall conditions, Re ∼ 10⁵
Dynamic stall is the abrupt flow separation from airfoils rapidly changing their orientation. This phenomenon, characterized by a delayed stall followed by a sharp drop in lift, has prompted efforts to prevent or delay it. This study aims to predict the lift of an airfoil randomly maneuvering under …
-
3D Dynamic Stall Simulation of Flow over NACA0012 Airfoil at 10⁵ and 10⁶ Reynolds Numbers
… an understanding of the physics behind the dynamic stall process by simulating the flow past pitching NACA-0012 airfoil at 100,000 and 1 million Reynolds number based on the chord length of the airfoil and at different reduced frequencies of 0.188 and 0.25 respectively in a three dimensional …
-
Analysis and reconstruction of dynamic-stall data from nominally two-dimensional aerofoil tests in two different wind tunnels
… and, here, not more than 0.2 M when considering dynamic-stall. This field of investigation, for the QinetiQ aerofoil, has been somewhat ignored till now to the advantage of higher speeds starting from 0.3 M. In order to improve the knowledge of the behaviour of aerofoils under M<0.2 conditions, …
-
Unsteady separation control on wind turbine blades
Dynamic stall is one of the primary causes of unsteady loads on wind turbine blades. The process can be instigated by a multitude of factors, common in wind turbine operating environments, such as inflow turbulence, wind gusts and sustained yaw misalignment. The unsteady separation due to dynamic …
-
Numerical and experimental study on the ability of dynamic roughness to alter the development of a leading edge vortex
Dynamic stall is an unsteady aerodynamic phenomenon garnering much research interest because it occurs in a variety of applications. For example, dynamic stall is known to occur on helicopter rotor blades, wind turbines, high maneuvering military aircraft, and flapping wings. Dynamic stall occurs …
-
The prediction of unsteady three-dimensional aerodynamics on wind turbine blades
After introducing the main features of the aerodynamics of wind turbines, a review of key theoretical studies and aerodynamic modelling methods provides the opportunity to focus on predictive methods and the main technical challenges associated with the aerodynamics of HAWTs. The basic aerodynamic …
-
A Fundamental Study of Advance Ratio, Solidity, Turbine Radius, and Blade Profile on the Performance Characteristics of Vertical Axis Turbines (VATs)
… ratio of 2.5 during which the blade experienced dynamic stall. This effect was also seen when the number of turbine blades was changed to four, at a solidity of 1.08. This negative impact on performance was found to be due to the increase in the drag component of the tangential force when dynamic …
-
Effects of temperature transients on the stall and stall recovery aerodynamics of a multi-stage axial flow compressor
… effects of inlet temperature transients on the stall and stall recovery aerodynamics of a low speed multi-stage axial flow compressor has been presented. Experiments were conducted on a low speed multi-stage axial flow compression system to demonstrate how a compressor dynamically stalls or …
-
Parallel Two-Dimensional Unstructured Anisotropic Delaunay Mesh Generation for Aerospace Applications
… Applications focusing on high-lift design or dynamic stall, or numerical methods and modeling test cases focus on two-dimensional domains. This push-button parallel mesh generation approach can generate high-fidelity unstructured meshes with anisotropic boundary layers for use in the …
-
Finite-State Airloads for Deformable Airfoils on Fixed and Rotating Wings
… wake and is generalized to include dynamic stall. The equations are placed in matrix form for ease of implementation. Comparison with other theories and with experimental data verifies the theory.
-
The Near Wake of a European Starling
… that the wings of a starling may undergo dynamic stall during flight. This is also implied by the results of the kinematic analysis of the bird’s wing motion and comparison to other flapping wing studies. Dynamic stall, thought to be limited to hovering and slow flight, would enable high …
-
Aerodynamic Response of a Two-Dimensional Cambered Wing at Low Reynolds Numbers in Steady-State Onset Turbulence
… flow were seen to experience a form of irregular dynamic stall. While sinusoidal-pitching did produce a similar effect on the time-averaged lift coefficient to onset turbulence, the transient behaviour was strongly reflective of the unsteady motion causing it. Furthermore, low-cost dynamic stall …
-
Direct numerical simulation of an aerofoil at high angle of attack and its control
… Reynolds number (Rec = 2×104) in completely stalled conditions has been carried out by means of Direct Numerical Simulations. The stalled condition is either a steady configuration at a fixed angle of attack (α = 20o) or it is reached via a ramp-up manoeuvre, increasing the angle of attack …
Page 1 of 2