Author: Kevin James StandishPublisher:
ISBN:
Category :
Languages : en
Pages : 330
Book Description
Aerodynamic Analysis of Blunt Trailing Edge Airfoils & a Micro-based Load Control System
Author: Kevin James StandishPublisher:
ISBN:
Category :
Languages : en
Pages : 330
Book Description
Aerodynamic Coefficients and Pressure Distribution on Blunt Trailing-edge Airfoils
Author: Allen Soong YapleeWind Tunnel and Numerical Analysis of Thick Blunt Trailing Edge Airfoils
Author: Anthony William McLennanPublisher:
ISBN: 9781124509174
Category :
Languages : en
Pages :
Book Description
Two-dimensional aerodynamic characteristics of several thick blunt trailing edge airfoils are presented. These airfoils are not only directly applicable to the root section of wind turbine blades, where they provide the required structural strength at a fraction of the material and weight of an equivalent sharp trailing edge airfoil, but are also applicable to the root sections of UAVs having high aspect ratios, that also encounter heavy root bending forces. The Reynolds averaged Navier-Stokes code, ARC2D, was the primary numerical tool used to analyze each airfoil. The UCD-38-095, referred to as the Pareto B airfoil in this thesis, was also tested in the University of California, Davis Aeronautical Wind Tunnel. The Pareto B has an experimentally determined maximum lift coefficient of 1.64 at 14 degrees incidence, minimum drag coefficient of 0.0385, and maximum lift over drag ratio of 35.9 at a lift coefficient of 1.38, 10 degrees incidence at a Reynolds number of 666,000. Zig-zag tape at 2% and 5% of the chord was placed on the leading edge pressure and suction side of the Pareto B model in order to determine the aerodynamic performance characteristics at turbulent flow conditions. Experimental Pareto B wind tunnel data and previous FB-3500-0875 data is also presented and used to validate the ARC2D results obtained in this study. Additionally MBFLO, a detached eddy simulation Navier-Stokes code, was used to analyze the Pareto B airfoil for comparison and validation purposes.
Experimental Investigation Into the Effectiveness of a Microtab Aerodynamic Load Control System
Author: Jonathon Paul BakerUnsteady Computational Investigations of Deploying Load-control Microtabs
Author: Raymond ChowTheoretical Aerodynamic Characteristics of Sharp and Circularly Blunt-wedge Airfoils
Author: Joseph W. ClearyPublisher:
ISBN:
Category : Aerodynamics, Hypersonic
Languages : en
Pages : 48
Book Description
Numerical solutions of the pressure distributions of blunt wedges for Mach numbers of 10 and ∞ are presented. The pressure distributions have been integrated to provide the inviscid lift, drag, and pitching-moment coefficients of any circularly blunt-wedge airfoil. The effects of varying surface angle, nose bluntness, and gas specific-heat ratio are discussed. A hypersonic wedge theory, derived from explicit oblique-shock equations, is introduced and is shown to predict accurately the loading and aerodynamic characteristics of surfaces with attached shocks. With appropriate account taken for nose bluntness, the theory is shown to be applicable to blunt airfoils.
Characterization and Estimation of Three-dimensional Structure in Unforced and Forced Blunt Trailing Edge Wake Flows
Author: Heather ClarkPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Blunt trailing edge airfoils offer structural and aerodynamic advantages in modern wind turbine and aircraft applications. However, penalties are introduced concurrently by vortex shedding at separation. In particular, the adverse effects of increased drag and unsteady loading motivate the development of a control strategy for the blunt trailing edge wake. Closed-loop control is pursued for its potentially greater effectiveness and efficiency, relative to open-loop forcing. Toward this aim, the thesis addresses the need for estimation of the state from limited measurements. The wake of a blunt trailing edge body is investigated experimentally through simultaneous measurements of velocity and the spanwise distribution of fluctuating surface pressure. Passive forcing is implemented with an array of vortex generators that are arranged according to the characteristic wavelength of the dominant small-scale instability. The guiding considerations for the analysis and discussion are physical characterization and the development of estimation strategies based on surface pressure. Joint examination of the measured variables through reduced-order modelling, wavelet analysis, and conditional averaging yields insight regarding the unsteady, three-dimensional nature of the flow. The investigation of forcing is focused upon the influence of the perturbation on the surface pressure and the performance of estimation models in the modified wake. It is found that low-frequency amplitude modulation of the pressure results from variation of both the magnitude of velocity fluctuations and the vortex formation length. The forcing regularizes the shedding in time and space, as evidenced by the attenuated modulation and enhanced spanwise coherence of the amplitude and phase. Examination of this behaviour confirms the connection between amplitude modulation and vortex dislocations in bluff body wakes. Several properties of the estimation approaches hold in general. It is shown that the phase is captured well, while the nonlinear relationship between the pressure and velocity presents a challenge for accurate estimation of the amplitude. Although the small-scale structure remains unobservable from the pressure sensing scheme, the large-scale spanwise variation of the wake is reproduced with equal fidelity by estimation models constructed in two orthogonal planes. The increased organization with forcing results in reduced estimation error, relative to the unforced case.
Navier-Stokes Analysis of Blunt Trailing Edge Airfoils
Author: Sharon K. StanawayAn Aerodynamic Analysis Computer Program and Design Notes for Low Speed Wing Flap Systems
Author: Boundary-layer Transition Prediction for Reynolds-averaged Navier-Stokes Methods
Author: Edward Anthony MaydaPublisher:
ISBN:
Category :
Languages : en
Pages : 358
Book Description