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Scott A Berry

Publications and source records attributed to Scott A Berry.

12 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2024

BOLT-2 Roughness Side Flight Data Results and Analysis

This report provides an in-depth review of the flight data obtained from Side B, also known as the roughness side, of BOLT-2, which was developed and designed to measure the effectiveness of boundary layer trips at hypersonic conditions. Three discrete-roughness trips were implemented on Side B at specific locations, with the necessary sensor layout, to investigate the flight conditions at which they no longer maintained turbulence behind them. All three trips were the same type that were scaled and sized based on predictions of local boundary layer thicknesses to provide the same level of effectiveness. One trip was on the vehicle centerline, where the boundary layer is relatively thick, while the other two were symmetrically located outboard where the boundary layer is much thinner. The relative difference in boundary layer thickness between these locations was roughly on the order of 3-to-1, thus the centerline trip was geometrically about three times larger than the outboard trips. A first order assessment of the Side B flight results is indicated by these three trips forcing transition onset at the same time during flight. The enclosed flight data shows that the performance of each individual trip was nearly identical, with allowances for minor variations attributed to measurement accuracy.

Flight Data↗
NASA NTRS2020

NASA Langley Aerothermodynamic Ground Tests in Support of the Boundary Layer Transition (BOLT) Flight Experiment

The Air Force Office of Scientific Research (AFOSR) has sponsored the Boundary Layer Transition (BOLT) Experiments to investigate hypersonic boundary layer transition on a low-curvature, concave surface with swept leading edges. This paper provides a review of aerothermodynamic ground test contributions by NASA Langley Research Center to the design of the BOLT flight experiment. Several test entries into the Langley Aerothermodynamics Laboratory 20-Inch Mach 6 Air Tunnel are discussed. Global surface heating distributions on subscale BOLT models were measured using either phosphor thermography or infrared thermography at a range of model attitudes and freestream Reynolds numbers. An initial test entry provided the first experimental measurements of transition on the BOLT geometry. A second test entry investigated the effects of distributed surface roughness along the swept leading edges. A third test entry provided an evaluation of the aeroheating environment on the aerodynamic fairings and a portion of the flight vehicle downstream of the BOLT experiment. These entries were intended to support the development and design of flight hardware and instrumentation for the BOLT flight experiment.

Elizabeth F Rieken↗
NASA NTRS2019

High-Speed Schlieren Analysis of Retropropulsion Jet in Mach 10 Flow

High-speed schlieren imaging of a 5-in.-diam, 70° sphere-cone model with a single centerline 15° half-angle nozzle was performed in a Mach 10 flow. Image sequences captured at 100 kHz were obtained with the nozzle plugged (fully blunted model), no nozzle flow, and with nozzle flow over a range of supply pressures. The freestream unit Reynolds number was kept constant for all runs at3.38×106m−1. Time-average information pertaining to the location, width, and stand-off distance of the bow shock, interface, terminal shock, and triple point as a function of jet pressure ratio are presented based on analysis of covariance images from each run. Measurement of jet plume boundary shape as a function of jet pressure ratio is also presented. Analyses of frequency content associated with the jet structure are shown, as are results of the proper orthogonal decomposition of these data. For all runs with nozzle flow, a dominant fundamental frequency of 2 kHz was observed. Finally, a discussion of bow shock unsteadiness resulting from interaction with freestream disturbances for the blunted and no nozzle flow is provided, as is a discussion on the formation of weak waves emanating from the bow shock resulting from this interaction.

Brett F Bathel↗
NASA NTRSDate not supplied

Secondary Side Considerations for the BOLT Flight Experiment

The Boundary Layer Transition (BOLT) Flight Experiment is preparing for launch in the Spring of 2020. Final designs decisions have been made to allow fabrication of hardware. The secondary side experiment, which was initially proposed to be a roughness experiment, was selected instead to be an investigation of step effects to provide better synergy with the primary side. Numerous design decisions have influenced the decision to revise and refine the goal of the secondary side, which is now to investigate the effects of rearward-facing steps. The present paper focused on the BOLT secondary side flight experiment, providing details of the key inputs and decisions made to finalize the flight vehicle and instrumentation.

Scott A Berry↗
NASA NTRSDate not supplied

Progress on the Development of a Step Height Sensor for the BOLT Flight Vehicle

This presentation will summarize progress on the development of a step height sensor for the BOLT flight vehicle. Two methods have been proposed to measure the step size in this effort.The first method involves the application of miniaturized camera embedded in the flight vehicle that views the step through a rearward-facing port (shown in Fig. 1a inset). The second method involves the application of a linear fiber optic array bundle to measure the intensity of light reflected back from the aft body step (concept shown in Fig. 1b). Preliminary testing with the miniaturized camera has been performed in the lab and shows that displacements of ≤10 μm can be measured using this method. Final testing with both methods will be performed on the test stand shown in Fig. 1a. This test stand will include a fine adjustment vertical translation stage that will be used to adjust the step height in steps of 1-2 μm. A high-magnification imaging system will also be used to verify the step height. The miniaturized camera and linear fiber optic array bundle will be mounted in one of several port holes with varying degrees of inclination relative to the top surface in the opposing aft-section slab. BOLT flight vehicle details and information on the steps can be found in Ref. [1].

BOLT↗
NASA NTRSDate not supplied

Development of the BOLT II Roughness Experiment for Flight

BOLT II is a sounding rocket research project with the goal of studying hypersonic boundary layer transition and turbulence. The BOLT II research vehicle is based on a three-dimensional geometry (a slightly longer version of BOLT) with concave surfaces and swept leading edges that provides two separate and distinct, also redundant, flow paths for conducting measurements. One side of BOLT II is dedicated to smooth surface transition and turbulence, to better study the natural instability processes, while the other has been assigned to study forced transition and turbulence using discrete roughness trips. The present paper is intended to document the primary drivers and decisions made leading up to finalizing the roughness side experiment for the BOLT II flight.

Hypersonic↗
NASA NTRSDate not supplied

Development of Optical Step Height Measurement Capability for the BOLT Flight Vehicle

This paper presents details on the development of testing procedures to evaluate two different optical step height sensors that were intended for use on the first and second Boundary Layer Transition (BOLT and BOLT II) flight vehicle as well as other flight vehicles. The accurate and precise measurement of step height at the interface of different sections of a flight vehicle is important, as small changes in the step height (in some instances < 10 microns) at such locations can have a significant influence on the development of a boundary layer over the outer surface of the vehicle, which in turn can significantly impact aeroheating (among other things). In this paper, testing procedures have been developed, and test hardware assembled, to determine the capabilities of two optical step height sensor candidates. The first candidate is a miniaturized camera sensor that would be embedded into the body of a flight vehicle and would image the interface between two sections of that vehicle. The second candidate is a small fiber-based optical sensor that would also be embedded into the body of the flight vehicle, but projects light onto the interface between two sections of the flight vehicle, and then monitors any reflected/scattered light from that interface. Preliminary data from these two sensor candidates are presented, and a discussion of improvements that will be made in the testing procedures and to the test hardware is provided.

Brett F Bathel↗
NASA NTRSDate not supplied

NASA LaRC Hypersonic Experimental Aerothermodynamic Capabilities and Recent Contributions

A review is presented of recent research, development, testing and evaluation aerothermodynamic activities that have been conducted at the NASA Langley Research Center in the Langley Aerothermodynamics Laboratory. An overview of the test facilities, model development and fabrication capabilities, and instrumentation and measurement techniques employed in this work is provided. Contributions to hypersonic flight and planetary exploration programs are detailed, as are fundamental research and development activities. Wind tunnel investigations are described that supported flight programs for NASA and Commercial Crew external partners. Collaborations between NASA projects and academia are also highlighted in this overview of recent wind tunnel experiments.

hypersonic↗
NASA NTRSDate not supplied

NASA Langley Hypersonic Experimental Aerothermodynamic Capabilities and Recent Contributions

A review is presented of recent research, development, testing and evaluation aerothermodynamic activities that have been conducted at the NASA Langley Research Center in the Langley Aerothermodynamics Laboratory. An overview of the test facilities, model development and fabrication capabilities, and instrumentation and measurement techniques employed in this work is provided. Contributions to hypersonic flight and planetary exploration programs are detailed, as are fundamental research and development activities. Wind tunnel investigations are described that supported flight programs for NASA and Commercial Crew external partners. Collaborations between NASA projects and academia are also highlighted in this overview of recent wind tunnel experiments.

hypersonic↗