Analysis and Comparison of Surface Roughness Effects on Pressure Data from SLS Wind Tunnel Test

Analysis and Comparison of Surface Roughness Effects on Pressure Data from SLS Wind Tunnel Test was conducted during Summer 2019 internship at Fluid Mechanics Lab. Student has been requested by academic adviser to present final presentation to aerospace department at university

Guide for Pressure-Sensitive Paint Testing at NASA Ames Research Center Unitary Plan Wind Tunnel

Optical measurement techniques have become a standard option for wind tunnel tests. Pressure-sensitive paint (PSP) is a mature test technique and a common experimental technique in many wind tunnels to measure the global mean static pressure on a model. PSP is a valuable tool when a more detailed distribution of the pressure is needed rather than the conventional pressure taps alone. Planning for a test with optical-based techniques can present new challenges even for experienced customer. The purpose of this paper is to provide a resource to the wind tunnel testing community and customers interested in obtaining PSP measurements on a wind tunnel model at the NASA Ames Research Centers Unitary Plan Wind Tunnel. An overview of PSP mechanics, a list of requirements for ones considering PSP measurements, and PSP deliverable details are specified

Simultaneous Boundary-Layer Transition, Tip Vortex, and Blade Deformation Measurements of a Rotor in Hover

This paper describes simultaneous optical measurements of a sub-scale helicopter rotor in the U.S. Army Hover Chamber at NASA Ames Research Center. The measurements included thermal imaging of the rotor blades to detect boundary layer transition; retro-reflective background-oriented schlieren (RBOS) to visualize vortices; and stereo photogrammetry to measure displacements of the rotor blades, to compute spatial coordinates of the vortices from the RBOS data, and to map the thermal imaging data to a three-dimensional surface grid. The test also included an exploratory effort to measure flow near the rotor tip by tomographic particle image velocimetry (tomo PIV)an effort that yielded valuable experience but little data. The thermal imaging was accomplished using an image-derotation method that allowed long integration times without image blur. By mapping the thermal image data to a surface grid it was possible to accurately locate transition in spatial coordinates along the length of the rotor blade

Global Skin-Friction Measurements Using Particle Image Surface FLow Visualization and a Luminescent Oil-Film

A quantitative global skin-friction measurement technique is proposed. An oil-film is doped with a luminescent molecule and thereby made to fluoresce in order to resolve oil-film thickness, and Particle Image Surface Flow Visualization is used to resolve the velocity field of the surface of the oil-film. Skin-friction is then calculated at location x as (x )xh, where x is the displacement of the surface of the oil-film and is the dynamic viscosity of the oil. The data collection procedure and data analysis procedures are explained, and preliminary experimental skin-friction results for flow over the wing of the CRM are presented

Comparison of Space Launch System Aerodynamic Surface Pressure Measurements from Experimental Testing and CFD

A comparison of surface pressure coefficient measurements obtained using pressure-sensitive paint (PSP) measurements with predictions from the computational fluid dynamics (CFD) code FUN3D is presented for the NASA SLS Block 1B crew vehicle. Overall, the flow features over the SLS configuration were captured by both the PSP data and CFD data at freestream Mach numbers (M(sub )) of 0.8 and 1.3. Overall, the flow features over the SLS are captured by the PSP data but the intensities of large pressure gradients are less intense than what was predicted by the CFD data. Several examples of this observation are given including the flow interaction at the booster nose cone edge, core body, and forward booster attachment hardware at M(sub ) = 0.8

Comparison of Experimental Surface and Flow Field Measurements to Computational Results of the Juncture Flow Model

Wing-body juncture flow fields on commercial aircraft configurations are challenging to compute accurately. The NASA Advanced Air Vehicle Program's juncture flow committee is designing an experiment to provide data to improve Computational Fluid Dynamics (CFD) modeling in the juncture flow region. Preliminary design of the model was done using CFD, yet CFD tends to over-predict the separation in the juncture flow region. Risk reduction wind tunnel tests were requisitioned by the committee to obtain a better understanding of the flow characteristics of the designed models. NASA Ames Research Center's Fluid Mechanics Lab performed one of the risk reduction tests. The results of one case, accompanied by CFD simulations, are presented in this paper. Experimental results suggest the wall mounted wind tunnel model produces a thicker boundary layer on the fuselage than the CFD predictions, resulting in a larger wing horseshoe vortex suppressing the side of body separation in the juncture flow region. Compared to experimental results, CFD predicts a thinner boundary layer on the fuselage generates a weaker wing horseshoe vortex resulting in a larger side of body separation

Comparison of Experimental Surface and Flow Field Measurements to Computational Results of the Juncture Flow Model

Wing-body juncture flow fields on commercial aircraft configurations are challenging to compute accurately. The NASA Advanced Air Vehicle Program's juncture flow committee is designing an experiment to provide data to improve Computational Fluid Dynamics (CFD) modeling in the juncture flow region. Preliminary design of the model was done using CFD, yet CFD tends to over-predict the separation in the juncture flow region. Risk reduction wind tunnel tests were requisitioned by the committee to obtain a better understanding of the flow characteristics of the designed models. NASA Ames Research Center's Fluid Mechanics Lab performed one of the risk reduction tests. The results of one case, accompanied by CFD simulations, are presented in this paper. Experimental results suggest the wall mounted wind tunnel model produces a thicker boundary layer on the fuselage than the CFD predictions, resulting in a larger wing horseshoe vortex suppressing the side of body separation in the juncture flow region. Compared to experimental results, CFD predicts a thinner boundary layer on the fuselage generates a weaker wing horseshoe vortex resulting in a larger side of body separation

DESIGNING THE SCIENTIFIC DATA SUPPLY CHAIN TO INCREASE KNOWLEDGE CREATION AND ACCELERATE SCIENTIFIC DISCOVERY VIA A MULTI-ARMED NEWSVENDOR MODEL

The rapid pace of technological advancement has resulted in a growth in data quantities and velocities across all industries, most notably in scientific research. Scientific user facilities owned and managed by the United States federal government are not-for-profit, aim to accelerate scientific discovery and increase knowledge creation by providing a system that supports users to solve difficult scientific issues, and have struggled with the challenge of how to fully use the promise of big data produced by a scientific experimental facility. Inability in the face of this adversity has substantially constrained the scientific research community’s capacity for breakthroughs in science. To tackle this challenge, we proposed a new hybrid model called the multi-armed newsvendor model and designed an integrated framework based on it with the intent of fostering scientific discovery. The multi-period newsvendor model emphasizes the importance of information sharing, while the multi-armed bandit framework instructs the customer on how to best address the exploration vs exploitation conundrum. Taking use of the synergy between the two models permits shorter exploratory runs and provides motivation for digitizing the data supply chain to promote near-real-time information sharing. Simulations on the proposed framework manifested by sharing information in real-time with a larger group of domain experts, the customer will maximize yields during a test campaign. Additionally, investigating a case study at NASA within the context of suggested treatment confirmed the striking financial savings in this area. The aerospace industry is poised to reap the benefits of the data deluge. Specifically in the design phase. The field is rich in physics-based models, and now rich in data. By viewing how the scientific data supply chain is currently arranged and application of the multi-armed newsvendor model, the benefits of information sharing give us reason to digitally transform the scientific data supply chain by changing the transportation method. The application of the multi-armed newsvendor model will see a broad impact in the areas of scientific research, as well as facility and engineering management. By innovating the transportation method of the scientific data supply chain, technical inclusion and technical accessibility will be enabled

PSP Course 2019

For investigations of pressure distri­butions on wind tunnel model surfaces with high spatial resolution, new experimental techniques such as Pressure Sensitive Paint (PSP) are required. Using this non-intrusive optical pressure measurement technique, spatial structures and/or rapid temporal or spatial changes of aerodynamic phenomena (transition from laminar to turbulent flow, shocks on pitching airfoils in transonic flows, coherent structures etc.) can be in­vestigated. Recently an increasing number of scientists and engineers has started to utilise the PSP technique to investigate pressure distributions in transonic, low speed, hypersonic and cryogenic wind tunnels, as well as in turbo machines. The PSP technique has also evolved from the measurement of steady state pressures to include both periodic and unsteady phenomena to study the instantaneous structure of pressure fields in various areas of fluid mechanics. This course, which is the eighth one on PSP organized by DLR Göttingen, Germany, will concentrate on both measurement techniques and aspects of the theory of PSP relevant to applications. In addition to lectures on the fundamental aspects of Pressure Sensitive Paint Systems, emphasis is placed on the presentation of practical and reliable solutions for problems faced during the implementation of the technique in wind tunnels and other test facilities. During practical sessions in the course, the participants will have the opportunity of carrying out experiments in small groups on PSP/TSP characterisation, coating technique, and the recording and evaluation of PSP/TSP data. Recent developments of the PSP/TSP technique will be discussed and demonstrated. In addition the application of Temperature Sensitive Paint (TSP), which is from the technical point of view very similar to PSP will be part of this course