Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “model scaling”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Results of an aerodynamic investigation of a space shuttle orbiter/747 carrier flight test configuration to determine separation characteristics utilizing 0.0125-scale models (48-0/AX1318I-1) in the LTV 4 x 4 foot high speed wind tunnel (CA26), volume 1

Results of tests conducted on a 0.0125-scale model of the Space Shuttle Orbiter and a 0.0125-scale model of the 747 CAM configuration in a 4 x 4-foot High Speed Wind Tunnel were presented. Force and moment data were obtained for each vehicle separately at a Mach number of 0.6 and for each vehicle in proximity to the other at Mach numbers of 0.3, 0.5, 0.6 and 0.7. The proximity effects of each vehicle on the other at separation distances (from the mated configuration) ranging from 1.5 feet to 75 feet were presented; 747 Carrier angles of attack from 0 deg to 6 deg and angles of sideslip of 0 deg and -5 deg were tested. Model variables included orbiter elevon, aileron and body flap deflections, orbiter tailcone on and off, and 747 stabilizer and rudder deflections.

Gillins, R. L.↗
NASA NTRS2010

Project M: Scale Model of Lunar Landing Site of Apollo 17

The basis of the project was creating a scale model representation of the Apollo 17 lunar landing site. Vital components included surface slope characteristics, crater sizes and locations, prominent rocks, and lighting conditions. The model was made for Project M support when evaluating approach and terminal descent as well as when planning surface operations with respect to the terrain. The project had five main mi lestones during the length of the project. The first was examining the best method to use to re-create the Apollo 17 landing site and then reviewing research fmdings with Dr. Tim Crain and EO staff which occurred on June 25, 2010 at a meeting. The second step was formulating a construction plan, budget, and schedule and then presenting the plan for authority to proceed which occurred on July 6,2010. The third part was building a prototype to test materials and building processes which were completed by July 13, 2010. Next was assembling the landing site model and presenting a mid-term construction status report on July 29, 2010. The fifth and final milestone was demonstrating the model and presenting an exit pitch which happened on August 4, 2010. The project was very technical: it needed a lot of research about moon topography, lighting conditions and angles of the sun on the moon, Apollo 17, and Autonomous Landing and Hazard Avoidance Technology (ALHAT), before starting the actual building process. This required using Spreadsheets, searching internet sources and conducting personal meetings with project representatives. This information assisted the interns in deciding the scale of the model with respect to cracks, craters and rocks and their relative sizes as the objects mentioned could interfere with any of the Lunar Landers: Apollo, Project M and future Landers. The project concluded with the completion of a three dimensional scale model of the Apollo 17 Lunar landing site. This model assists Project M members because they can now visualize approach phase, terminal descent phase, and surface phase operations on the physical model. The project had an additional requirement that was also satisfied: the granite table the model was placed on must be returnable to its original condition if needed in the future.

O'Brien, Hollie↗
NASA NTRS1987

Aeroelasticity and mechanical stability report, 0.27 Mach scale model of the YAH-64 advanced attack helicopter

A 27% dynamically scaled model of the YAH-64 Advanced Attack Helicopter main rotor and hub has been designed and fabricated. The model will be tested in the NASA Langley Research Center V/STOL wind tunnel using the General Rotor Model System (GRMS). This report documents the studies performed to ensure dynamic similarity of the model with its full scale parent. It also contains a preliminary aeroelastic and aeromechanical substantiation for the rotor installation in the wind tunnel. From the limited studies performed no aeroelastic stability or load problems are projected. To alleviate a projected ground resonance problem, a modification of the roll characteristics of the GRMS is recommended.

Straub, F. K.↗
NASA NTRS1996

RSRM 10 percent Scale Model Drilled Hole Plate Tests

The RSRM 10% Scaled Model under design will make use of drilled hole liners to provide mass addition along the axial length of the model. The model will have two sets of liners in use at a time. The outer most liner is a flow distribution tube, the purpose of which is to help distribute the flow evenly over each model segment. The inner most liner will simulate the propellant burning surface at a burn time of 80 seconds. This liner will replicate as closely as possible the actual geometry of the full scale RSRM at the 80 second burn time. In order to obtain the correct mass flow rate for the burn time selected, it is necessary to determine the porosity of the holes drilled in each liner and the performance of those holes. The pressure drop across the liners directly effects the uniformity of the flow in the axial direction for a given model section. It is desired to have a pressure drop across the liners which is greater than the axial pressure drop in a given section. However, the pressure drop across the liner also has a bearing on the structural soundness of the model. The performance of the model was determined analytically, but there was some uncertainty as to the value of the discharge coefficient used. This uncertainty was the impetus for these drilled hole plate tests. Experimentally obtaining the discharge coefficients for sample plates of the porosity to be used in the model would increase the fidelity of the model design. These tests were developed in order to provide the required information with the least amount of testing time and hardware.

Purinton, David C.↗
NASA NTRS1972

A thermal scale modeling study for Apollo and Apollo applications, volume 2

The development and demonstration of practical thermal scale modeling techniques applicable to systems involving radiation, conduction, and convection with emphasis on cabin atmosphere/cabin wall thermal interface are discussed. The Apollo spacecraft environment is used as the model. Four possible scaling techniques were considered: (1) modified material preservation, (2) temperature preservation, (3) scaling compromises, and Nusselt number preservation. A thermal mathematical model was developed for use with the Nusselt number preservation technique.

Shannon, R. L.↗
NASA NTRS1981

Analysis of data from a wind tunnel investigation of a large-scale model of a highly maneuverable supersonic V/STOL fighter - STOL configuration

The surface pressure and thermal characteristics of a large-scale model of a highly maneuverable supersonic fighter with STOL capability are described. The 7.28 m span model is powered by two J-97 turbojets, operated at 9340 N thrust. It combines upper-surface and spanwise blowing to augment the lift characteristics over a wide angle-of-attack range. The most significant feature of the fighter's flow field is the leading edge vortex that forms at low alphas, grows stronger, and moves inboard as alpha is increased. Upper surface blowing enhanced the lift on the wing in both stalled and unstalled areas significantly, while generating only a modest aft shift in the center of pressure. Lift gains were greatest at high alphas and with the flap deflected. Spanwise blowing was most significant at angles-of-attack greater than 8 deg, when the jet strengthened the vortex. The 1100 F spanwise blowing jet mixed very rapidly with the wing flow field, creating a maximum temperature rise of only 300-350 F. A comparison of small-scale and large-scale model wing pressure characteristics showed similar trends created by upper surface blowing, while spanwise blowing characteristics differed considerably. Force data correlated well with semi-empirical predictions for gross thrust coefficients less than 1.0.

Falarski, M. D.↗
NASA NTRS1987

Measurements of natural circulation flow in a scale model PWR reactor system during postulated degraded core accidents using laser anemometry

The natural circulation of a single-phase fluid in a scale-model pressurized water reactor system was studied during a postulated degraded core accident. A half section of a one-seventh scale model with a plexiglass adiabatic window was employed. Water and SF6 were used as the fluid. LDA was used to perform velocity measurements along the center plane of the model at five elevations. It was found that the recirculation flow patterns are nearly symmetric except near the hot legs and in the upper head and that the fluid in the upper plenum is well mixed.

Kadambi, J. R.↗
NASA NTRS1986

Pressure distributions obtained on a 0.10-scale model of the space shuttle Orbiter's forebody in the AEDC 16T propulsion wind tunnel

Pressure distribution test data obtained on a 0.10-scale model of the forward fuselage of the Space Shuttle Orbiter are presented without analysis. The tests were completed in the AEDC 16T Propulsion Wind Tunnel. The 0.10-scale model was tested at angles of attack from -2 deg to 18 deg and angles of side slip from -6 to 6 deg at Mach numbers from 0.25 to 1/5 deg. The tests were conducted in support of the development of the Shuttle Entry Air Data System (SEADS). In addition to modeling the 20 SEADS orifices, the wind-tunnel model was also instrumented with orifices to match Development Flight Instrumentation (DFI) port locations that existed on the Space Shuttle Orbiter Columbia (OV-102) during the Orbiter Flight Test program. This DFI simulation has provided a means of comparisons between reentry flight pressure data and wind-tunnel and computational data.

Siemers, P. M., III↗
NASA NTRS1957

Aerodynamic Characteristics of a 0.04956-Scale Model of the Convair TF-102A Airplane at Transonic Speeds, Coord. No. AF-120

The basic aerodynamic characteristics of a 0.04956-scale model of the Convair TF-102A airplane with controls undeflected have been determined at Mach numbers from 0.60 to 1.135 for angles of attack up to approximately 22 deg in the Langley 8-foot transonic tunnel. In addition, comparisons have been made with data obtained from a previous investigation of a 0.04956-scale model of the Convair F-102A airplane. The results indicated the TF-102A airplane was longitudinally stable for all conditions tested. An increase in lift-curve slope from 0.045 to 0.059 and an 11-percent rearward shift in aerodynamic-center location occurred with increases in Mach number from 0.60 to approximately 1.05. The zero-lift drag coefficient for the TF-102A airplane increased 145 percent between the Mach numbers of 0.85 and 1.075; the maximum lift-drag ratio decreased from 9.5 at a Mach number of 0.60 to 5.0 at Mach numbers above 1.025. There was little difference in the lift and pitching-moment characteristics and drag due to life between the TF-102A and F-102A configurations. However, as compared with the F-102A airplane, the zero-lift drag-rise Mach number for the TF-102A was reduced by at least 0.06, the zero-lift peak wave drag was increased 50 percent, and the maximum lift-drag ratio was reduced as much as 20 percent.

Osborne, Robert S.↗
NASA NTRS1993

Application of a dynamic subgrid-scale model to turbulent recirculating flows

The dynamic subgrid-scale model of Germano et al. is implemented in a finite volume formulation and applied to the simulation of turbulent flow in a three-dimensional lid-driven cavity at Reynolds number of 7500. The filtering operation is carried out in physical space, and the model coefficient is calculated locally. The computed mean and rms velocities as well as the Reynolds stress are compared with experimental data. It is shown that backscatter from small to large scales is necessary to sustain turbulent fluctuations. The model is being applied to the simulation of turbulent flows in a stratified and rotating environment in complex geometries.

Zang, Y.↗
NASA NTRS1972

Operations and maintenance manual for a scale-model lunar roving vehicle

A one-sixth scale model of the lunar roving vehicle used in the Apollo 15 mission was built and instrumented to conduct model studies of vehicle mobility. The model was free running under radio control and was equipped with a lightweight telemetry transmitter that allowed 16 channels of data to be gathered simultaneously. String payout and fifth-wheel devices were developed to measure vehicle velocity. Other real-time measurements included wheel torque, wheel speed, center-of-gravity accelerations, and steering forces. Calibration, operations, and maintenance procedures were worked out. Details of the development of the instrumentation, its maintenance, and some of the problems encountered, are recorded serve as a preliminary operations and maintenance manual for this specific model. In addition, information regarding soil processing and testing that may be useful to NASA personnel planning mobility research with the model in soil is furnished.

Lessem, A. S.↗
NASA NTRS1974

Acoustic and aerodynamic testing of a scale model variable pitch fan

A fully reversible pitch scale model fan with variable pitch rotor blades was tested to determine its aerodynamic and acoustic characteristics. The single-stage fan has a design tip speed of 1160 ft/sec (353.568 m/sec) at a bypass pressure ratio of 1.5. Three operating lines were investigated. Test results show that the blade pitch for minimum noise also resulted in the highest efficiency for all three operating lines at all thrust levels. The minimum perceived noise on a 200-ft (60.96 m) sideline was obtained with the nominal nozzle. At 44% of takeoff thrust, the PNL reduction between blade pitch and minimum noise blade pitch is 1.8 PNdB for the nominal nozzle and decreases with increasing thrust. The small nozzle (6% undersized) has the highest efficiency at all part thrust conditions for the minimum noise blade pitch setting; although, the noise is about 1.0 PNdB higher for the small nozzle at the minimum noise blade pitch position.

Jutras, R. R.↗
NASA NTRS2008

A Goddard Multi-Scale Modeling System with Unified Physics

A multi-scale modeling system with unified physics has been developed at NASA Goddard Space Flight Center (GSFC). The system consists of an MMF, the coupled NASA Goddard finite-volume GCM (fvGCM) and Goddard Cumulus Ensemble model (GCE, a CRM); the state-of-the-art Weather Research and Forecasting model (WRF) and the stand alone GCE. These models can share the same microphysical schemes, radiation (including explicitly calculated cloud optical properties), and surface models that have been developed, improved and tested for different environments. The following is presented in this report: (1) a brief review of the GCE model and its applications on the impact of aerosols on deep precipitation processes, (2) the Goddard MMF and the major difference between two existing MMFs (CSU MMF and Goddard MMF), and preliminary results (the comparison with traditional GCMs), and (3) a discussion on the Goddard WRF version (its developments and applications).

Tao, Wei-Kuo↗
NASA NTRS2010

A Goddard Multi-Scale Modeling System with Unified Physics

A multi-scale modeling system with unified physics has been developed at NASA Goddard Space Flight Center (GSFC). The system consists of an MMF, the coupled NASA Goddard finite-volume GCM (fvGCM) and Goddard Cumulus Ensemble model (GCE, a CRM); the state-of-the-art Weather Research and Forecasting model (WRF) and the stand alone GCE. These models can share the same microphysical schemes, radiation (including explicitly calculated cloud optical properties), and surface models that have been developed, improved and tested for different environments. In this talk, I will present: (1) A brief review on GCE model and its applications on the impact of the aerosol on deep precipitation processes, (2) The Goddard MMF and the major difference between two existing MMFs (CSU MMF and Goddard MMF), and preliminary results (the comparison with traditional GCMs), and (3) A discussion on the Goddard WRF version (its developments and applications). We are also performing the inline tracer calculation to comprehend the physical processes (i.e., boundary layer and each quadrant in the boundary layer) related to the development and structure of hurricanes and mesoscale convective systems. In addition, high - resolution (spatial. 2km, and temporal, I minute) visualization showing the model results will be presented.

Tao, Wei-Kuo↗