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Technical Paper

Pressure-Sensitive Paint Technology Applied to Low-Speed Automotive Testing

Pressure-sensitive paint (PSP) technology is a technique used to experimentally determine surface pressures on models during wind tunnel tests. The key to this technique is a specially formulated pressure-sensitive paint that responds to, and can be correlated with the local air pressure. Wind tunnel models coated with pressure-sensitive paint are able to yield quantitative pressure data on an entire model surface in the form of light intensity values in recorded images. Quantitative results in terms of pressure coefficients (Cp) are obtained by correlating PSP data with conventional pressure tap data. Only a small number of surface taps are needed to be able to obtain quantitative pressure data with the PSP method. This technique is gaining acceptance so that future automotive wind tunnel tests can be done at reduced cost by eliminating most of the expensive pressure taps from wind tunnel models.
Technical Paper

Testing of the Prototype Plant Research Unit Subsystems

The Plant Research Unit (PRU) is currently under development by the Space Station Biological Research Project (SSBRP) team at NASA Ames Research Center (ARC) with a scheduled launch in 2001. The goal of the project is to provide a controlled environment that can support seed-to-seed and other plant experiments for up to 90 days. This paper describes testing conducted on the major PRU prototype subsystems. Preliminary test results indicate that the prototype subsystem hardware can meet most of the SSBRP science requirements within the Space Station mass, volume, power and heat rejection constraints.
Technical Paper

Test Techniques for STOVL Large-Scale Powered Models

Predicting and testing for hover performance, both in and out of ground effect, and transition performance, from jet- to wing-borne flight and back, for vertical/short takeoff and landing (V/STOL) configurations can be a difficult task. Large-scale testing of these configurations can provide for a better representation of the flow physics than small-scale testing. This paper will discuss some of the advantages in testing at large-scale and some test techniques and issues involved with testing large-scale STOVL models. The two premier test facilities for testing large- to full-scale STOVL configurations are the Outdoor Aerodynamic Research Facility (OARF) and the 80- by 120-Foot Wind Tunnel of the National Full-Scale Aerodynamics Complex (NFAC). Other items of discussion will include force and moment measurements, jet efflux decay, wall effects, tunnel flow breakdown, strut interference, and flow visualization options.
Technical Paper

Hover/Ground-Effect Testing and Characteristics for a Joint Strike Fighter Configuration

Hover and ground-effect tests were conducted with the Lockheed-Martin Large Scale Powered Model (LSPM) during June-November 1995 at the Outdoor Aerodynamics Research Facility (OARF) located at NASA Ames Research Center. This was done in support of the Joint Strike Fighter (JSF) Program being lead by the Department of Defense. The program was previously referred to as the Joint Advanced Strike Technology (JAST) Program. The tests at the OARF included: engine thrust calibrations out of ground effect, measurements of individual nozzle jet pressure decay characteristics, and jet-induced hover force and moment measurements in and out of ground effect. The engine calibrations provide data correlating propulsion system throttle and nozzle settings with thrust forces and moments for the bare fuselage with the wings, canards, and tails removed. This permits measurement of propulsive forces and moments while minimizing any of the effects due to the presence of the large horizontal surfaces.
Technical Paper

The NASA Ames Controlled Environment Research Chamber - Present Status

The Controlled Environment Research Chamber (CERC) at the NASA Ames Research Center was created for early-on investigation of promising new technologies for life support of advanced space exploration missions. The CERC facility is being used to address the advanced technology requirements necessary to implement an integrated working and living environment for a planetary habitat. The CERC, along with a human-powered centrifuge, a planetary terrain simulator, advanced displays, and a virtual reality capability, is able to develop and demonstrate applicable technologies for future planetary exploration. There will be several robotic mechanisms performing exploration tasks external to the habitat that will be controlled through the virtual environment to provide representative workloads for the crew.
Technical Paper

Development of an Advanced Life Support Testbed at the Amundsen-Scott South Pole Station

This paper presents a description of the Controlled Ecological Life Support System (CELSS) Antarctic Analog Project (CAAP) and its functionality as a pilot study for the design of a future Lunar-Mars habitat. A description of the prototype development testbed, located at Ames Research, is provided as well as an analysis of the key design parameters. The CAAP program is tasked with the development of a life support testbed at the South Pole. This facility will include food production, waste processing, and in situ energy production capabilities. The testbed will provide NASA with a remote facility located in an extremely harsh environment which has been designed to provide a useful analog to the deployment of a future Lunar-Martian habitat. NASA's program goals are the operational testing of life support technologies and the conduct of scientific studies to facilitate future technology selection and system design.
Technical Paper

The CELSS Antarctic Analog Project: A Validation of CELSS Methodologies at the South Pole Station

The CELSS Antarctic Analog Project (CAAP) is a joint NSF and NASA project tor the development, deployment and operation of CELSS technologies at the Amundsen-Scott South Pole Station. CAAP is implemented through the joint NSF/NASA Antarctic Space Analog Program (ASAP), initiated to support the pursuit of future NASA missions and to promote the transfer of space technologies to the NSF. As a joint endeavor, the CAAP represents an example of a working dual agency cooperative project. NASA goals are operational testing of CELSS technologies and the conduct of scientific study to facilitate technology selection, system design and methods development required for the operation of a CELSS. Although not fully closed, food production, water purification, and waste recycle and reduction provided by CAAP will improve the quality of life for the South Pole inhabitants, reduce logistics dependence, and minimize environmental impacts associated with human presence on the polar plateau.
Technical Paper

Space Simulation in the Neutral Buoyancy Test Facility

Various methods have been used to simulate reduced gravity environments for space systems research and development. Neutral buoyancy has been the most universally used simulation of zero-g. This paper describes the facilities, personnel and experimental work that are associated with the Neutral Buoyancy Test Facility (NBTF) at NASA Ames Research Center (ARC). This facility provides a unique underwater environment for the researcher to simulate reduced gravity activities and evaluate the performance of space-related equipment. The NBTF's small size gives it several advantages over larger water facilities. First, a smaller crew ensures a lower overhead. Second, the facility is used for research purposes only, eliminating any scheduling conflicts with astronaut training. Lastly, the small volume of water allows the researcher to more easily vary the water temperature. This feature is ideal for investigations of astronaut thermal comfort and regulation.
Technical Paper

Boundary-Layer Transition and Global Skin Friction Measurement with an Oil-Fringe Imaging Technique

A new oil-fringe imaging skin friction (FISF) technique to measure skin friction on wind tunnel models is presented. In the method used to demonstrate the technique, lines of oil are applied on surfaces that connect the intended sets of measurement points, and then a wind tunnel is run so that the oil thins and forms interference fringes that are spaced proportional to local skin friction. After a run the fringe spacings are imaged with a CCD-array digital camera and measured on a computer. Skin friction and transition measurements on a two-dimensional wing are presented and compared with computational predictions.
Technical Paper

Aerodynamic Tailoring of the Learjet Model 60 Wing

The wing of the Learjet Model 60 was tailored for improved aerodynamic characteristics using the TRANAIR transonic full-potential CFD code. A root leading edge glove and wing tip fairing were shaped to reduce shock strength, improve cruise drag and extend the buffet limit. The aerodynamic design was validated by wind tunnel test and flight test data.
Technical Paper

Fecal Simulant Delivery Systems for Parabolic Flight Testing of the Flexible Membrane Commode

The Flexible Membrane Commode (FMC) is an alternative waste management system designed to address the severe mass restrictions on the Orion vehicle. The concept includes a deployable seat and single use, three layer bags that employ air flow to draw solids away from the body and safely contain them in disposable bags.1 Simulated microgravity testing of the system was performed during two separate parabolic flight campaigns in July and August of 2008. Experimental objectives included verifying the waste fill procedures in reduced gravity, characterizing waste behavior during the filling process, and comparison of the results with model predictions. In addition the operational procedure for bag installation, removal, and sealing were assessed. 2 A difficult operational requirement concerns the delivery of the fecal waste simulant into the upper area of the bag in a manner that faithfully simulates human defecation.
Technical Paper

Development of a Reduced Gravity Test Rig for Waste Management

The space environment presents many challenges to the operation and functioning of life support systems. These challenges include reduced gravity, near vacuum ambient, extreme temperatures, and radiation. Proper testing and modeling of system components to account for these factors will be important for their verification. This paper describes the modeling and design of a reduced gravity test rig for waste management studies. The first investigation planned relate to the functioning of components of the Flexible Membrane Commode (FMC) currently under development at NASA Ames Research Center. The planned reduced gravity tests will be carried out in NASA's C'9 aircraft which provides approximately 25 seconds of reduced gravity per parabolic trajectory. The filling of the commode bag under the influence of a directed air flow will be studied. Simulated waste will be injected and cabin air will be used for directing the waste into the bag.
Technical Paper

Development of Variable Camber Continuous Trailing Edge Flap for Performance Adaptive Aeroelastic Wing

This paper summarizes the recent development of an adaptive aeroelastic wing shaping control technology called variable camber continuous trailing edge flap (VCCTEF). As wing flexibility increases, aeroelastic interactions with aerodynamic forces and moments become an increasingly important consideration in aircraft design and aerodynamic performance. Furthermore, aeroelastic interactions with flight dynamics can result in issues with vehicle stability and control. The initial VCCTEF concept was developed in 2010 by NASA under a NASA Innovation Fund study entitled “Elastically Shaped Future Air Vehicle Concept,” which showed that highly flexible wing aerodynamic surfaces can be elastically shaped in-flight by active control of wing twist and bending deflection in order to optimize the spanwise lift distribution for drag reduction. A collaboration between NASA and Boeing Research & Technology was subsequently funded by NASA from 2012 to 2014 to further develop the VCCTEF concept.
Technical Paper

Coaxial Rotor Flow Phenomena in Forward Flight

Coaxial rotors are finding use in advanced rotorcraft concepts. Combined with lift offset rotor technology, they offer a solution to the problems of dynamic stall and reverse flow that often limit single rotor forward flight speeds. In addition, coaxial rotorcraft systems do not need a tail rotor, a major boon during operation in confined areas. However, the operation of two counter-rotating rotors in close proximity generates many possible aerodynamic interactions between rotor blades, blades and vortices, and between vortices. With two rotors, the parameter design space is very large, and requires efficient computations as well as basic experiments to explore aerodynamics of a coaxial rotor and the effects on performance, loads, and acoustics.
Technical Paper

Aerodynamic Drag Reduction of the Underbody of a Class-8 Tractor-Trailer

Experimental measurements of a 1:20-scale tractor-trailer configuration were obtained in the 48- by 32-Inch Subsonic Wind Tunnel at NASA Ames Research Center. The model included significant details of the underbody geometries of both the tractor and trailer. In addition, the tractor included a flow-through grill and a simplified engine block to provide an approximation of the flow through the engine compartment. The experiment was conducted at a Reynolds Number of 430,000 for yaw angles between ±14 deg. The measurements included forces and moments and static surface pressures for various underbody configurations. Simple fairings on the underbodies of the tractor and trailer both yielded a reduction in the wind-averaged drag coefficient of 0.018 (2.7%) when tested separately. A horizontal plate designed to block vertical flow in the tractor-trailer gap provided marginally higher drag reduction (0.021, or 3.2%).
Technical Paper

Detailed Experimental Results of Drag-Reduction Concepts on a Generic Tractor-Trailer

The 1/8-scale Generic Conventional Model was studied experimentally in two wind tunnels at NASA Ames Research Center. The investigation was conducted at a Mach number of 0.15 over a Reynolds number range from 1 to 6 million. The experimental measurements included total and component forces and moments, surface pressures, and 3-D particle image velocimetry. Two configurations (trailer base flaps and skirts) were compared to a baseline representative of a modern tractor aero package. Details of each configuration provide insight into the complex flow field and the resulting drag reduction was found to be sensitive to Reynolds number.
Technical Paper

Reactive Carbon from Life Support Wastes for Incinerator Flue Gas Cleanup

This paper presents the results from a joint research initiative between NASA Ames Research Center and Lawrence Berkeley National lab. The objective of the research is to produce activated carbon from life support wastes and to use the activated carbon to adsorb and chemically reduce the NOx and SO2 contained in incinerator flue gas. Inedible biomass waste from food production is the primary waste considered for conversion to activated carbon. Results to date show adsorption of both NOx and SO2 in activated carbon made from biomass. Conversion of adsorbed NOx to nitrogen has also been observed.
Technical Paper

Assessment of the Vapor Phase Catalytic Ammonia Removal (VPCAR) Technology at the MSFC ECLS Test Facility

The Vapor Phase Catalytic Ammonia Removal (VPCAR) technology has been previously discussed as a viable option for the Exploration Water Recovery System. This technology integrates a phase change process with catalytic oxidation in the vapor phase to produce potable water from exploration mission wastewaters. A developmental prototype VPCAR was designed, built and tested under funding provided by a National Research Announcement (NRA) project. The core technology, a Wiped Film Rotating Device (WFRD) was provided by Water Reuse Technologies under the NRA, whereas Hamilton Sundstrand Space Systems International performed the hardware integration and acceptance test of the system. Personnel at the Ames Research Center performed initial systems test of the VPCAR using ersatz solutions. To assess the viability of this hardware for Exploration Life Support (ELS) applications, the hardware has been modified and tested at the MSFC ECLS Test Facility.
Technical Paper

Microphone Array Phased Processing System (MAPPS): Phased Array System for Acoustic Measurements in a Wind Tunnel

A processing system has been developed to meet increasing demands for detailed noise measurement of aircraft in wind tunnels. Phased arrays enable spatial and amplitude measurements of acoustic sources, including low signal-to-noise sources not measurable by conventional measurement techniques. The Microphone Array Phased Processing System (MAPPS) provides processing and visualization of acoustic array measurements made in wind tunnels. The system uses networked parallel computers to provide noise maps at selected frequencies in a near real-time testing environment. The system has been successfully used in two subsonic, hard-walled wind tunnels, the NASA Ames 7- by 10-Foot Wind Tunnel and the NASA Ames 12-Foot Wind Tunnel. Low level airframe noise that can not be measured with traditional techniques was measured in both tests.
Technical Paper

3D PIV in Wind Tunnel Applications: Measurements of a Truck Wake

Three-component Particle Image Velocimetry (3D PIV) is a fluid velocity measurement technique that has evolved from the laboratory to become a method appropriate for use in large-scale wind tunnel testing. An example application of 3D PIV in a wind tunnel test is described. The PIV technique was applied to characterize the wake of The Ground Transportation System (GTS) model developed for the Department of Energy (DOE) Heavy Vehicle Drag Reduction (HVDR) program. The test was performed in the Ames/Army 7×10 foot wind tunnel. The objective of the PIV measurements was to validate the HVDR computational fluid dynamics code. The PIV method and PIV system are described. Sample truck wake data with and without boattail attachments are shown. 3D PIV system successfully captured the effects of the boattails on the truck wake.