Aerodynamics and Fluid Mechanics Commons^™

Avoiding Aircraft Icing Accidents, Nihad E. Daidzic

Aviation Department Publications

No abstract provided.

Chilling Out In The Sim: The Need For Icing Training., Nihad E. Daidzic

Aviation Department Publications

No abstract provided.

Multidisciplinary Design Optimization Of An Extreme Aspect Ratio Hale Uav, Bryan J. Morrisey

Master's Theses

ABSTRACT

Multidisciplinary Design Optimization of an Extreme Aspect Ratio HALE UAV

Bryan J. Morrisey

Development of High Altitude Long Endurance (HALE) aircraft systems is part of a vision for a low cost communications/surveillance capability. Applications of a multi payload aircraft operating for extended periods at stratospheric altitudes span military and civil genres and support battlefield operations, communications, atmospheric or agricultural monitoring, surveillance, and other disciplines that may currently require satellite-based infrastructure. Presently, several development efforts are underway in this field, including a project sponsored by DARPA that aims at producing an aircraft that can sustain flight for multiple years and …

Computational Solution Of Tail Buffet Response And Active Flow Control, Kaushik Laxmikant Joshi

Mechanical & Aerospace Engineering Theses & Dissertations

In this thesis, numerical simulation of the multidisciplinary method for prediction and control of vortex induced tail buffeting is studied using delta wing-single tail configuration. Flow conditions are chosen such that wing vortex cores experience vortex breakdown and the resulting wake flow impinges on the vertical tail. The aero/structure problem is solved sequentially using three sets of equations on a multi-block grid structure. To obtain aerodynamic loading on the tail, the fluid flow around the wing-tail assembly is computed by time-accurately solving unsteady, laminar, compressible Navier-Stokes equations using an implicit, upwind, flux-difference splitting finite volume scheme. Then the aeroelastic equations …

Cfd As Applied To The Design Of Short Takeoff And Landing Vehicles Using Circulation Control, Tyler M. Ball

Master's Theses

The ability to predict the distance required for an aircraft to takeoff is an essential component of aircraft design. It involves aspects related to each of the major aircraft systems: aerodynamics, propulsion, configuration, structures, and stability and control. For an aircraft designed for short takeoffs and landings (STOL), designing the aircraft to provide a short takeoff distance, or more precisely the balanced field length (BFL), often leads to the use of a powered lift technique such as circulation control (CC). Although CC has been around for many years, it has never been used on a production aircraft. This is in …

Aerodynamic And Acoustic Investigations Of An Advanced Over-The-Wing Nacelle Transport Aircraft Configuration, Geoffrey A. Hill

Mechanical & Aerospace Engineering Theses & Dissertations

The transonic aerodynamic and low-speed acoustic characteristics of an advanced, Over-the-Wing Nacelle (OWN), subsonic transport configuration are assessed. The cruise aerodynamics of the OWN were analyzed using both inviscid Euler and viscous Navier-Stokes CFD. Results of the assessments are compared to a similar configuration with a more traditional Under-the-Wing Nacelle (UWN) installation and a similar reference Wing-Body Qualitative observations and quantitative drag computations are made for the three configurations at a cruise Mach number of0.78, an approximate altitude of35,000-ft, and a C_L, of 0.44. It was found that the OWN's novel inboard wing channel design is effective in …

Global Modeling Of Pitch Damping From Flight Data, Noah M. Favaregh

Mechanical & Aerospace Engineering Theses & Dissertations

Flight testing using a designed experiment was used to model pitch damping in the longitudinal short-period mode of an aircraft. Multi-step elevator maneuvers were flown at different angles of attack and power levels on an electrically powered, propeller-driven UltraStick 120 remotely controlled model A Central Composite Response Surface Design was used to select angle of attack and power levels for each maneuver. During post flight analysis it was discovered that power was not measured correctly for this purpose so advance ratio was selected as a replacement factor. Parameter estimation results for each maneuver were modeled globally using a single response …

Computational Sensing And Closed-Loop Active Flow Control Of Airfoil At Post-Stall Conditions, Volkan Kamaci

Mechanical & Aerospace Engineering Theses & Dissertations

Flow separation over lifting aerodynamic components, such as airfoils and wings, occurs during stall conditions which are caused by adverse changes (i.e. high angle of attack, inflow conditions, etc.) in the operating conditions of aerodynamic components. During stall conditions, the flow over airfoil loses its momentum, creating high pressure zones on the upper surface of the airfoil and even a small increase in pressure causes the fluid particles to stop and separate to a low pressure zone. In order to eliminate the flow separation, the low momentum flow should be removed in order to maintain the high momentum and low …

Numerical Study Of Combustion Of Hydrogen And Ethylene In A Two-Dimensional Dual-Mode Scramjet Combustor, Robert A. Carson

Mechanical & Aerospace Engineering Theses & Dissertations

This thesis presents computational fluid dynamics results for two-dimensional flow geometries utilizing two fuels, hydrogen (H2) and ethylene (C2H4). Upstream interaction was evident with the use of both fuels due in part to recirculation in the combustor, the inlet pressures and the combustion process. Results were obtained for hydrogen using a reduced chemical kinetic model while results obtained for ethylene employed a reduced chemical kinetic model as well as an expanded chemical kinetic model.

Initially, an examination of grid composition was conducted in order to select the most numerically efficient and accurate grid for reacting flow in the current combustor …

A Numerical Analysis Of A Non-Porous, Flexible Upper Airfoil Surface, Asao Omura

Mechanical & Aerospace Engineering Theses & Dissertations

The aerodynamic behavior of the early Wright brothers' airfoils is an important element of the history of aeronautics. Their fabric-covered wings were not constrained to maintain the airfoil shape of their wooden rib substructures and therefore differences in performance between rigid and flexible Wright airfoil shapes can be expected. The purpose of this thesis was to develop a systematic numerical approach that allows an assessment of the influence of the fabric on the overall aerodynamic behavior of the Wright Model B airfoil. The Model B airfoil was chosen because it is the earliest "production" airfoil and has sufficient documentation to …

Numerical Studies Of Transition For Flows Around Multi-Element Airfoils, Fengjun Liu

Dissertations

The transition of flows around a multi-element airfoil has been numerically studied using RANS with a k - e two-equation transition model, LST and DNS. The transition model uses an effective eddy-viscosity by coupling an intermittence-like correction to a turbulence eddy-viscosity that can be obtained via solving a parent k - e turbulence model. The transition model is truly predictive in that it is able to predict transition onset locations without having to specify prior knowledge of the targeted transition process. The predicted transition onset locations for all the cases studied were compared with the measured data. The results suggest …

The Effectiveness Of Film Cooling In A Hypersonic Flowfield With Favorable Pressure Gradients, Julie A. Young

Mechanical & Aerospace Engineering Theses & Dissertations

The impetus of this technical document is to report results of aerothermodynamic cooling of a scramjet nozzle under favorable pressure gradients. The goals of film cooling are to protect the nozzle skin from the high enthalpy combustor flow, reduce regenerative cooling requirements, and decrease nozzle skin friction. A hypersonic nozzle configuration for which experimental data exists was selected as the basis of this numerical study. As a first step, the numerical results of film cooling along a flat plate are compared to previous literature to validate the numerical model. Subsequently, computations are performed to study the effects of varying the …

Study Of Surface Heat Exchangers For High-Altitude Atmospheric Research Aircraft, Te-Kang Wang

Mechanical & Aerospace Engineering Theses & Dissertations

A flush-mounted heat exchanger concept, using the wing surface to dissipate heat, is investigated as a lower drag alternative to conventional ducted plate-fin radiators. A feasibility analysis is made for an unmanned high-altitude aircraft which will reach altitudes up to 25 kilometers. A computer code is used to calculate approximate heat transfer coefficients over the airfoil's surface. A model is tested in the Old Dominion University subsonic wind tunnel to verify the results of the computer code. The results indicate that a flush mounted heat exchanger design is able to provide 20 to 100 percent of the required heat dissipation …

Computation Of The Aerodynamic Characteristics Of A Subsonic Transport Aircraft Using A Panel Method, Lillianne Plaster Whitelock Troeger

Mechanical & Aerospace Engineering Theses & Dissertations

An advanced low-order panel method, VSAERO, is applied to a full-configuration transport aircraft. Wing pressure distributions as well as lift, drag, and pitching moment coefficients calculated for the full computational configuration are compared with experimental data. In addition, partial configurations are evaluated computationally to determine the relevance of certain complex aircraft components to the computations. It is shown that the wing-surface pressure distributions and pitching moment coefficient are well predicted by VSAERO. The lift coefficient is consistently overpredicted by the code.

An Experimental And Analytical Investigation Of Wing Flutter On A Trial Rotor V/Stol Aircraft, David L. Soistmann

Mechanical & Aerospace Engineering Theses & Dissertations

A wind tunnel model based on a trail rotor vehicle concept was tested for wing flutter in the subsonic flow regime. The wind tunnel model was flutter tested in the forward flight mode only. From this test it was determined that this conceptual vehicle may be susceptible to wing flutter. However, the flutter encountered was not catastrophic but was of the limited amplitude type. The trailing rotor blades were found to have a positive aerodynamic damping effect on flutter. The flutter mechanism for each flutter point was due to a coupling of the first wing bending and first wing torsion …

Numerical Simulation Of Turbulent Flows Past Three-Dimensional Cavities, Shivakumar Srinivasan

Mechanical & Aerospace Engineering Theses & Dissertations

Computations have been performed to simulate turbulent supersonic, transonic, and subsonic flows past three-dimensional deep, transitional, and shallow cavities. Simulation of these self sustained oscillatory flows has been generated through time accurate solutions of Reynolds averaged full Navier-Stokes equations using the explicit MacCormack scheme. The Reynolds stresses have been modeled, using the Baldwin-Lomax algebraic turbulence model with certain modifications. The computational results include instantaneous and time averaged flow properties everywhere in the computational domain. Time series analyses have been performed for the instantaneous pressure values on the cavity floor. Comparison with experimental data is made in terms of the mean …

Weatherford Air Show And General Thomas P. Stafford Museum Dedication, City Of Weatherford

Programs

This is a program from the 1987 Weatherford Air Show and General Thomas P. Stafford Museum Dedication in Weatherford, Oklahoma.

Unless stated otherwise within this repository collection, all materials are shared under the following Creative Commons license: [Creative Commons Attribution-NonCommercial 4.0 International License].

Second Annual Great Oklahoma Balloon Race & Airshow Gala Reception, Clarence E. Page Oklahoma Air And Space Museum

Programs

This is the program from the second annual Great Oklahoma Balloon Race & Airshow Gala Reception in honor of Astronaut, Lt. General Thomas P. Stafford. The event was held at the Clarence E. Page Oklahoma Aviation and Space Hall of Fame and Museum in the Kirkpatrick Center in OKC, OK, on Thursday, August 16th, 1984.

Unless stated otherwise within this repository collection, all materials are shared under the following Creative Commons license: [Creative Commons Attribution-NonCommercial 4.0 International License].

An Analytical Design Procedure For The Determination Of Effective Leading Edge Extensions On Thick Delta Wings, Farhad Ghaffari

Mechanical & Aerospace Engineering Theses & Dissertations

An analyt1cal des1gn procedure for Lead1ng-Edge Extensions (LEE) has been developed for thick delta wings. This LFE device is des1gned to be mounted to a w1ng along the pseudo-stagnation stream surface associated w1th the attached flow design lift coeff1cient of greater than zero. The intended purpose of the device is to improve the aerodynamic performance of high subsonic and low super son1c aircraft at incidences above that of attached flow design lift coefficient, by us1ng a vortex system emanating along the leading edges of the device. The low pressure assoc1ated with these vort1ces would act on the LEE upper surface …

Interaction Of A Two-Dimensional Transverse Jet With A Supersonic Mainstream, Gilbert Otto Kraemer

Mechanical & Aerospace Engineering Theses & Dissertations

A experimental investigation of the interaction of a twodimensional sonic jet injected transversely into a confined main flow has been conducted. The main flow consisted of air at a Mach number of 2.9. The effects of varying the jet parameters on the flow field were examined using surface pressure and composition data. Also, the downstream flow field was examined using static pressure, pitot pressure, and composition profile data. The jet parameters varied were gapwidth, jet static pressure, and injectant species of either helium or nitrogen. The values of the jet parameters used were 0.039, 0.056,and 0.109 cm for the gapwidth …

Experimental Study Of Delta Wing Leading-Edge Devices For Drag Reduction At High Lift, Thomas Dwight Johnson Jr.

Mechanical & Aerospace Engineering Theses & Dissertations

Future fighter aircraft requirements specify efficient supersonic cruise and high-g maneuverability at high lift. The slender delta wing meets the first requirement but has large lift induced drag increments at high lift. One method to alleviate the drag is to control the flow at the wing leading edge (LE) by means of small LE devices, so as to maintain locally attached flow to higher angles of attack and thus increase the level of aerodynamic thrust.

The devices selected for evaluation were the fence, slot, pylon-type vortex generator (VG), and sharp leading-edge extension (SLEE). These devices were tested on a 60° …

Apollo/Soyuz Tv Guide: "Soyuz, Soyuz, This Is Apollo...", Bob Button

Articles

This is a TV Guide from 1975 that features a story about the televised Apollo/Soyuz mission.

Computer-Aided Design Of Light Aircraft To Meet Certain Aerodynamic And Structural Requirements, Joanne Lynn Walsh

Mechanical & Aerospace Engineering Theses & Dissertations

Nonlinear mathematical programming techniques are applied to a particular aircraft design problem, that of determining the maximum range design for light aircraft subject to certain aerodynamic and structural requirements. Search techniques available in an existing nonlinear optimization computer program, AESOP, are applied to the design problem. Seven design variables are used to define the wing dimensions, the wing skin thickness, the cruise velocity, the amount of fuel carried, and the engine horsepower. The influence of different design requirements on the range is observed and discussed.

The Analysis Of A Subsonic Jet Issuing Perpendicular To A Freestream Flow From A Flat Plate And A Body Of Revolution, Donald R. Haberman

Mechanical & Aerospace Engineering Theses & Dissertations

An investigation was undertaken to determine the nature of the pressure region around a jet issuing perpendicular to a free stream flow from a flat plate and a cylindrical surface, and to determine the forces which resulted from such a pressure region. It was also attempted to develop an empirical relation to enable the prediction of surface pressure regions from known physical parameters.

The jet was exhausted from a 0.375 inch nozzle perpendicular to a free stream flow of about 90 ft./sec. The flow rate of the jet was then varied to give three free stream to jet velocity ratios …

Astronaut Activity Involving Pete Conrad, Elliot See, Thomas Stafford And Ed White, Nasa

Videos

Astronaut Activity Involving Pete Conrad, Elliot See, Thomas Stafford and Ed White

• This item documents the time period of July 8, 1963–July 12, 1963.