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Technical Paper

Wind Tunnel Experiments with Anti-Icing Fluids

2011-06-13
2011-38-0078
An experimental methodology for investigating the effects of anti-icing fluids is presented in this paper. A wing model was designed, fabricated, and instrumented for testing anti-icing fluids in a wind tunnel facility. In addition, a video capturing method was developed and used to document fluid behavior during simulated takeoff tests. The experiments were performed at the Wichita State University 2.13-m by 3.05-m (7-ft by 10-ft) wind tunnel facility with two pseudoplastic fluids representative of Type IV anti-icing fluids. The experimental data obtained included fluid wave propagation speeds, chordwise fluid thickness distributions as a function of time, and boundary layer velocity profiles for the clean and fluid contaminated wing model at select chordwise stations. During simulated takeoffs with initial fluid depths of either 4 mm or 2 mm, the fluids were observed to thin in the forward (upstream) regions of the wing model and accumulate in the aft regions.
Technical Paper

The Post-Stall Effect of Gurney Flaps on a NACA-0011 Airfoil

1996-05-01
961316
The effect of Gurney flaps on a NACA 0011 airfoil was investigated. Gurney flaps provide a substantial increase in lift while the penalty in drag is small. With the Gurney flap, the airfoil pressure distribution shows increased suction on the upper surface and higher pressure on the lower surface compared to the clean airfoil. This change in pressure is most profound on the lower surface just in front of the Gurney flap. Since separation occurs on the upper surface upon stall, this higher pressure condition on the lower surface continues into the post-stall regime. Thus, the NACA 0011 airfoil with Gurney flaps generates lift coefficients greater than one even under post-stall conditions.
Technical Paper

The Effect of Gurney Flaps on Three-Dimensional Wings with and without Taper

1996-10-01
965514
The effect of Gurney flaps on three-dimensional wings was investigated in the 7x10 feet low speed wind tunnel. There have been a number of studies on Gurney flaps in recent years. However, these studies have been limited to two-dimensional airfoils. A comprehensive investigation on the effect of Gurney flaps for a wide range of configurations and test conditions was conducted at Wichita State University. In this part of the investigation, straight and tapered three-dimensional wings with Natural Laminar Flow (NLF) airfoil sections were tested. Gurney flaps spanning 4.5, 3.0, and 1.5 feet were tested on a straight NLF wing of 5 feet span. Compared to the clean wing, the 4.5 feet span 0.017c and 0.033c height Gurney flaps increased the maximum lift coefficient by 17% and 22%, respectively. The increase in maximum lift coefficient was proportionately smaller with the shorter span Gurney flaps.
Technical Paper

The Design of a Flexible Fixture for Aircraft Assembly

1996-10-01
961885
Two new concept of flexible fixture subsystem (FFS) for aircraft wing spar assembly are introduced in this paper. The advantages and characteristics of FFS are discussed and compared with the current assembly method and fixtures. The objective of FFS is to replace the dedicated tooling and be able to quickly reconfigure itself for new types of spars. The fixture enables a family of spars to be mounted and assembled in the same tooling. Left- and right-hand side spars, varying lofts(spar cap angles), height, and depths are all accommodated on the same tool, within its envelop.
Technical Paper

The Design and Development of an Energy Absorbing Commuter Seat

1995-05-01
951163
The motivation for this project was to design, and develop an aircraft seat to meet the proposed FAA 32g vertical/longitudinal dynamic test requirements specified in NPRM 93-71. A major goal of the design was to develop a production-quality seat in terms of weight, comfort, appearance, simplicity, and manufacturability. The relevant injury criteria was to obtain an occupant lumbar (spinal) load below 6670 N (1500 1bf). The design incorporated energy absorbing devices in the cushion and chair legs. The seat developed was based on the Beech King Air design and incorporated a modified seat frame, seat back, and reclining mechanism. The seat cushions were provided by Oregon Aero, while the seat pan and seat legs were designed and manufactured at WSU.
Technical Paper

Study of Drill Tool Geometry in High Speed Drilling of Aluminum Sheet Metal

1999-06-05
1999-01-2295
The present scenario of increasing the production rates in drilling demands high speed drilling while at the same time maintaining the quality of the drilled holes. Of the many factors that affect the high-speed drilling process, such as speed, feed rate, material of drill and work piece, and drill geometry this study attempts only to study the effect of drill geometry in high-speed drilling of aluminum sheet metal. In the Experiments conducted, different speeds, feed rates and drill bits of varying geometry are utilized in order to study their effects on hole quality as it relates to hole diameter and burr formation. Also the variation of thrust and torque with increase in speed over a speed range of 6,000 to 30,000 rpm has been studied.
Technical Paper

Streamwise Computation of Axisymmetric Parabolized Flows

1996-05-01
961298
A new algorithm to compute parabolized axisymmetric flows is presented. Axi-symmetric flows are computed using Χ, distance along the centerline line of the duct, and ξ, the stream function, as the independent variables. The dependent variables used are U(Χ, ξ), the streamwise velocity, and R(Χ, ξ), the cross-stream coordinate of the stream surface with value of the stream function equal to ξ. Since the value of stream function is constant along the duct walls, this choice of variables makes it easy to satisfy the boundary conditions; and, thus eliminates the need for an externally generated boundary fitted grid. Sample computations are presented for incompressible parabolized developing laminar flow through pipes and diffusers. The results of the computations are compared with the available experimental data.
Technical Paper

Quality Improvement of Manual Riveting Machine Process

1995-05-01
951188
Since riveting operations on airplane panels are usually performed manually by skilled workers and unrecoverable tolerances or errors are possible. In this paper, a semi-automated riveting system, which improves the product quality, and reduces cost, is proposed. The system setup is illustrated while related technology is described. The system uses optical equipment along with computer vision technology to assist riveting operators to find the locations of the rivets automatically, which may help reduce some setup procedures for riveting operations.
Technical Paper

Novel and Inexpensive Method of Performing Dynamic Wind Tunnel Model Testing

1995-09-01
951988
An investigation was performed to evaluate a novel and inexpensive wind tunnel model mount for dynamic aerodynamic testing. A computer analysis code was developed to identify the dimensions of the control surface needed to produce a desired pitching motion for a delta wing. The code was then used to design and build a dynamic model apparatus that was evaluated in a low speed wind tunnel at Wichita State University. The dynamic model mount and control were evaluated for a variety of motions, including constant pitch rate ramps, constant frequency oscillations and impulse or step inputs. Results from the ramp and oscillation test indicated the system is very responsive and capable of a wide range of motion.
Technical Paper

Navier-Stokes Computations of Multi-Element Airfoils Using Various Turbulence Models

1995-05-01
951180
The flow about multi-element airfoil configurations is investigated using the unsteady Reynolds averaged Navier-Stokes equations. An explicit scheme is used to advance the solution in time while a finite difference scheme is applied to discretize the flux terms. An algebraic and two one-equation turbulence models are used to model turbulence. The domain about each multi-element airfoil is discretized with structured Chimera grids. The multi-element configurations presented in this paper include two airfoils with slotted flaps and an airfoil with a 50% chord vented aileron deflected at 90 degrees. Subsonic flow computations are performed for attached and separated flow conditions. The computational results obtained with the CRTVD code developed at Wichita State University are in good correlation with wind tunnel data and with computational results obtained with the INS2D computer code developed at NASA Ames research center.
Technical Paper

Exploratory Applications of New Aerodynamic Control Devices

1995-05-01
951429
A new class of aerodynamic control devices have recently been designed specifically for wind turbine applications. These new controls were tested to evaluate their effectiveness in modulating wind turbine power output and for slowing or stopping a wind turbine in high wind or loss of generator situations. While these control devices were developed specifically for wind turbine applications, there exists the possibility that alternate aviation uses exist. In particular, these trailing-edge control devices were evaluated for reducing aircraft landing distances, generating rapid rates of descent, deep stall or spin recovery and for high angle of attack control.
Technical Paper

Experimental and Computer Model Results for a Bleed Air Ice Protection System

2011-06-13
2011-38-0034
Results from a two-dimensional computer model developed at Wichita State University (WSU) for bleed air system analysis are compared with experimental data from icing tunnel tests performed with a wing model equipped with a hot air ice protection system. The computer model combines a commercial Navier-Stokes flow solver with a steady-state thermodynamic analysis model that applies internal flow heat transfer correlations to compute wing leading edge skin temperatures and the location and extent of the runback ice. The icing tunnel data used in the validation of the computer model were obtained at the NASA Icing Research Tunnel using representative in-flight icing conditions and a range of bleed air system mass flows and hot air temperatures. Correlation between experiment and analysis was good for most of the test cases used to assess the performance of the simulation model.
Technical Paper

Experimental Investigation of Gurney Flaps on Reflection Plane Wing with Fuselage and/or Nacelle

1997-05-01
971468
An experimental investigation on the effects of Gurney flaps on a reflection plane model was conducted. Two sizes of Gurney flaps were tested on a series of configurations which included a tapered wing (with a NLF-0215 airfoil section), a fuselage, a nacelle, and their permutations. The tests were conducted at a Reynolds number of 1.0 million based on mean chord. Results indicated that lift and drag were increased upon using the Gurney flaps; lift to drag and lift squared to drag ratios were also increased. In particular, the lift to drag ratio for the complete “airplane” was almost the same with or without a small Gurney flap. Pitching moment became more negative (nose-down) with the Gurney flap, and positive (nose-up) with the addition of the fuselage.
Technical Paper

Evaluation of a Basic Doppler Global Velocimetry System

1995-05-01
951427
A basic one-component Doppler Global Velocimetry (DGV) system has been developed at Wichita State University. This system was evaluated on a round axisymmetric jet. The results are compared with measurements made using traditional Constant Temperature Anemometry (CTA) and Preston tube measurements at 3.2, 9.6 and 16.0 jet exit diameters downstream and along the jet centerline. The DGV results show similar trends to these measurements. Software corrections for camera misalignment, optical distortions, and laser frequency variations were necessary to assure data quality. Results indicate good agreement between the DGV and CTA measurements exist.
Technical Paper

Environmental Durability of Aircraft Aluminum Alloy Skin Materials

1993-05-01
931229
This paper compares the environmental durability of currently used as well as some of the potential aircraft aluminum alloy skin materials. A simple test was developed to evaluate the environmental durability by simultaneous application of fatigue loads and aerated salt water attack. Alclad alloys showed excellent resistance to corrosion fatigue. On the other hand, 7475 alloy and new potential material 6013 alloy experienced inter-granular corrosion at the fatigue crack origin area. The test results also indicated the significance of corrosion preventive coatings to increase the age of aircraft.
Technical Paper

Design of an Internal Balance for a Wind Tunnel Ruddevator Model

1995-05-01
951187
A wind tunnel balance was designed to measure the aerodynamic loads on a ruddevator system during tests in the WSU 7′ x 10′ wind tunnel. The design goal for the system was to produce a balance that could accurately uncouple the components of the aerodynamic loads such that the lift, pitching moment and rolling moment relative to the balance reference point could be measured separately. This was a challenge because of the dimensional constraints and because of the accuracy requirement for a large range of possible load distributions during the tests. A simple flat plate idealization of the actual balance system was designed for laboratory structural tests to investigate some possible balance design strategies prior to the construction of the actual balance. Specific parameters of interests during these tests were that of choice of material, level of response of the structure to simulated service loads and strain gage selection and circuit design.
Technical Paper

Computation of the Base Flow for Axisymmetric Nacelle Configurations

1997-05-01
971466
A flow modeling method has been developed to analyze the flow in the annular base (rear-facing surface) of a circular engine nacelle flying at subsonic speed but with a supersonic exhaust jet. Real values of exhaust gas properties and temperature are included. Potential flows of the air and gas streams are computed for the flow past a separated wake. Then a viscous jet mixing is superimposed on this inviscid solution. Conservation of mass, momentum and energy is achieved by mutiple iterations. Despite the iterations, the wake flow field is computed with modest computer requirements.
Technical Paper

Comparison of Experimental and Computational Ice Shapes for a Swept Wing Model

2011-06-13
2011-38-0093
Two-dimensional and three-dimensional leading edge ice shapes for a finite wing model computed with the NASA Glenn LEWICE 2.0 and LEWICE3D Version 2 ice accretion codes are compared with experimental data from icing tunnel tests. The wing model had 28° leading edge sweep angle, 1.52-m (60-in) semispan and an airfoil section representative of business jet wings. Experimental wing leading edge ice shapes were obtained at the NASA Glenn Icing Research Tunnel (IRT) for six icing conditions. Tests conditions included angles of attack of 4° and 6°, airspeeds ranging from 67.06 m/s (150 mph) to 111.76 m/s (250 mph), static air temperatures in the range of -11.28°C (11.7°F) to -2.78°C (27°F), liquid water contents of 0.46 g/m₃, 0.51 g/m₃, and 0.68 g/m₃, and median volumetric diameters of 14.5 μm and 20 μm.
Technical Paper

Comparative Study of One- and Two-Equation Turbulence Models

1997-05-01
971481
Separated flows and subsequent formation of shear layers are important fluid processes which play a dominant role in numerous engineering applications. Prediction of this fluid process is an important element in the design and analysis of highspeed vehicles and, ultimately, in the performance and trajectory analysis. The prediction methodology used in the current study includes the numerical solution of the Navier-Stokes equations on a multi-block grid system. Several turbulence models are used to investigate their performance for compressible, turbulent, separated and shear layer flows. The computational results are compared to available experimental data.
Technical Paper

Comparative Analysis of Navier-Stokes Codes - Accuracy and Efficiency

1993-04-01
931385
Flow field computations and, in particular, that of pressure, skin friction, and heat transfer (for high speed flights) are the primary parameters in the design of aerospace vehicles. Most computational schemes based on either the inviscid Euler equations or various forms of the Navier-Stokes equations are remarkably accurate in the predictions of pressure distributions. However, computations of skin friction and heat transfer particularly at high speeds have been a source of considerable difficulty. Problems arise not only due to the grid resolution but also due to the particular numerical scheme employed. To address the difficulty associated with accurate computations of the velocity and temperature gradients, a comparative investigation of several Navier- Stokes codes is undertaken. Previous studies with regard to the effect of grid resolution are incorporated into the current investigation.
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