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Articles 61 - 90 of 337

Full-Text Articles in Aerospace Engineering

Double Wall Cooling Of An Effusion Plate With Simultaneous Cross Flow And Impingement Jet Array Internal Cooling, Phil Ligrani, Austin Click, David Ritchie, Federico Liberatore, Rajeshriben Patel, Yin-Hsiang Ho Dec 2019

Double Wall Cooling Of An Effusion Plate With Simultaneous Cross Flow And Impingement Jet Array Internal Cooling, Phil Ligrani, Austin Click, David Ritchie, Federico Liberatore, Rajeshriben Patel, Yin-Hsiang Ho

PRC-Affiliated Research

The present study considers comparisons of hot-side effusion plate results for a mainstream flow passage with CR = 1 and for a mainstream flow passage with CR = 4. The coolant supply arrangement for both CR contraction ratio values includes simultaneous use of cross flow and an impingement jet array. For the effusion cooled/hot surface, presented are spatially-resolved distributions of surface adiabatic film cooling effectiveness, and surface heat transfer coefficients (measured using infrared thermography). These results are given for main flow Reynolds numbers Rems of 89,900 to 95,800. For this main flow Reynolds number range, four different combination values of …


Double Wall Cooling Of An Effusion Plate With Simultaneous Cross Flow And Impingement Jet Array Internal Cooling, Phil Ligrani, Austin Click, David Ritchie, Federico Liberatore, Rajeshriben Patel, Yin-Hsiang Ho Dec 2019

Double Wall Cooling Of An Effusion Plate With Simultaneous Cross Flow And Impingement Jet Array Internal Cooling, Phil Ligrani, Austin Click, David Ritchie, Federico Liberatore, Rajeshriben Patel, Yin-Hsiang Ho

PRC-Affiliated Research

The present study considers comparisons of hot-side effusion plate results for a mainstream flow passage with CR = 1 and for a mainstream flow passage with CR = 4. The coolant supply arrangement for both CR contraction ratio values includes simultaneous use of cross flow and an impingement jet array. For the effusion cooled/hot surface, presented are spatially-resolved distributions of surface adiabatic film cooling effectiveness, and surface heat transfer coefficients (measured using infrared thermography). These results are given for main flow Reynolds numbers Rems of 89,900 to 95,800. For this main flow Reynolds number range, four different combination values of …


Analysis Of Shock Wave Unsteadiness Using Space And Time Correlations Applied To Shadowgraph Flow Visualization Data, Shannon Marko, Phillip M. Ligrani Dec 2019

Analysis Of Shock Wave Unsteadiness Using Space And Time Correlations Applied To Shadowgraph Flow Visualization Data, Shannon Marko, Phillip M. Ligrani

PRC-Affiliated Research

Unsteady flow characteristics of a normal shock wave, a lambda foot, and a separated turbulent boundary layer are investigated within a unique test section with supersonic inlet flow. The supersonic wind tunnel facility, containing this test section, provides a Mach number of approximately 1.54 at the test section entrance. Digitized shadowgraph flow visualization data are employed to visualize shock wave structure within the test section. These data are analyzed to determine shock wave unsteadiness characteristics, including grayscale spectral energy variations with frequency, as well as time and space correlations, which give coherence and time lag properties associated with perturbations associated …


Analysis Of Shock Wave Unsteadiness Using Space And Time Correlations Applied To Shadowgraph Flow Visualization Data, Shannon Marko, Phillip M. Ligrani Dec 2019

Analysis Of Shock Wave Unsteadiness Using Space And Time Correlations Applied To Shadowgraph Flow Visualization Data, Shannon Marko, Phillip M. Ligrani

PRC-Affiliated Research

Unsteady flow characteristics of a normal shock wave, a lambda foot, and a separated turbulent boundary layer are investigated within a unique test section with supersonic inlet flow. The supersonic wind tunnel facility, containing this test section, provides a Mach number of approximately 1.54 at the test section entrance. Digitized shadowgraph flow visualization data are employed to visualize shock wave structure within the test section. These data are analyzed to determine shock wave unsteadiness characteristics, including grayscale spectral energy variations with frequency, as well as time and space correlations, which give coherence and time lag properties associated with perturbations associated …


Analysis Of Shock Wave Unsteadiness Using Space And Time Correlations Applied To Shadowgraph Flow Visualization Data, Shannon Marko, Phillip M. Ligrani Dec 2019

Analysis Of Shock Wave Unsteadiness Using Space And Time Correlations Applied To Shadowgraph Flow Visualization Data, Shannon Marko, Phillip M. Ligrani

PRC-Affiliated Research

Unsteady flow characteristics of a normal shock wave, a lambda foot, and a separated turbulent boundary layer are investigated within a unique test section with supersonic inlet flow. The supersonic wind tunnel facility, containing this test section, provides a Mach number of approximately 1.54 at the test section entrance. Digitized shadowgraph flow visualization data are employed to visualize shock wave structure within the test section. These data are analyzed to determine shock wave unsteadiness characteristics, including grayscale spectral energy variations with frequency, as well as time and space correlations, which give coherence and time lag properties associated with perturbations associated …


2019 Summer-Fall Graduate Recognition Program, Propulsion Research Center, Robert Frederick Dec 2019

2019 Summer-Fall Graduate Recognition Program, Propulsion Research Center, Robert Frederick

PRC Graduate Recognition

This program includes the graduate recognition program for summer and fall 2019. Includes photographs, upcoming events, recent publications, and student profiles.


Entrapped Oxide Formation In The Friction Stir Weld (Fsw) Process, Judy Schneider, Poshou Chen, Arthur C. Nunes Jr. Oct 2019

Entrapped Oxide Formation In The Friction Stir Weld (Fsw) Process, Judy Schneider, Poshou Chen, Arthur C. Nunes Jr.

PRC-Affiliated Research

The ultimate design values for a friction stir weld (FSW) are not based on the average strength, but the lowest strength or outlier. Thus, the robustness of the process could be ultimately increased by understanding and minimizing the sources of data scatter within the mechanical properties of a FSW panel. Internal voids are known to result in reduced strength, but are detectable using non-destructive evaluation (NDE). Other metallurgical discontinuities, such as internal oxides, are difficult to detect using NDE and are often blamed for random variations in the mechanical properties of FSWs. Current efforts to minimize internal oxides within a …


Entrapped Oxide Formation In The Friction Stir Weld (Fsw) Process, Judy Schneider, Poshou Chen, Arthur C. Nunes Jr. Oct 2019

Entrapped Oxide Formation In The Friction Stir Weld (Fsw) Process, Judy Schneider, Poshou Chen, Arthur C. Nunes Jr.

PRC-Affiliated Research

The ultimate design values for a friction stir weld (FSW) are not based on the average strength, but the lowest strength or outlier. Thus, the robustness of the process could be ultimately increased by understanding and minimizing the sources of data scatter within the mechanical properties of a FSW panel. Internal voids are known to result in reduced strength, but are detectable using non-destructive evaluation (NDE). Other metallurgical discontinuities, such as internal oxides, are difficult to detect using NDE and are often blamed for random variations in the mechanical properties of FSWs. Current efforts to minimize internal oxides within a …


Entrapped Oxide Formation In The Friction Stir Weld (Fsw) Process, Judy Schneider, Poshou Chen, Arthur C. Nunes Jr. Oct 2019

Entrapped Oxide Formation In The Friction Stir Weld (Fsw) Process, Judy Schneider, Poshou Chen, Arthur C. Nunes Jr.

PRC-Affiliated Research

The ultimate design values for a friction stir weld (FSW) are not based on the average strength, but the lowest strength or outlier. Thus, the robustness of the process could be ultimately increased by understanding and minimizing the sources of data scatter within the mechanical properties of a FSW panel. Internal voids are known to result in reduced strength, but are detectable using non-destructive evaluation (NDE). Other metallurgical discontinuities, such as internal oxides, are difficult to detect using NDE and are often blamed for random variations in the mechanical properties of FSWs. Current efforts to minimize internal oxides within a …


Oh Production And Jet Length Of An Atmospheric-Pressure Plasma Jet For Soft And Biomaterial Treatment, Ryan P. Gott, Kunning G. Xu Oct 2019

Oh Production And Jet Length Of An Atmospheric-Pressure Plasma Jet For Soft And Biomaterial Treatment, Ryan P. Gott, Kunning G. Xu

PRC-Affiliated Research

Atmospheric-pressure plasma jets (APPJs) are currently being studied and developed for the biomedical, chemistry, and physics communities because of their ability to produce desirable reactive species at low temperatures and at atmospheric pressures. Due to the high particle densities, small scales, and nonequilibrium nature of these plasmas, they can be difficult to predict and compare across devices. In this article, a plasma jet is operated over a range of conditions and characterized by using optical emission spectroscopy (OES) and synchronized imaging. The effect of the operating conditions on the gas temperature, jet length, plasma formation, and reactive species produced is …


Oh Production And Jet Length Of An Atmospheric-Pressure Plasma Jet For Soft And Biomaterial Treatment, Ryan P. Gott, Kunning G. Xu Oct 2019

Oh Production And Jet Length Of An Atmospheric-Pressure Plasma Jet For Soft And Biomaterial Treatment, Ryan P. Gott, Kunning G. Xu

PRC-Affiliated Research

Atmospheric-pressure plasma jets (APPJs) are currently being studied and developed for the biomedical, chemistry, and physics communities because of their ability to produce desirable reactive species at low temperatures and at atmospheric pressures. Due to the high particle densities, small scales, and nonequilibrium nature of these plasmas, they can be difficult to predict and compare across devices. In this article, a plasma jet is operated over a range of conditions and characterized by using optical emission spectroscopy (OES) and synchronized imaging. The effect of the operating conditions on the gas temperature, jet length, plasma formation, and reactive species produced is …


Oh Production And Jet Length Of An Atmospheric-Pressure Plasma Jet For Soft And Biomaterial Treatment, Ryan P. Gott, Kunning G. Xu Oct 2019

Oh Production And Jet Length Of An Atmospheric-Pressure Plasma Jet For Soft And Biomaterial Treatment, Ryan P. Gott, Kunning G. Xu

PRC-Affiliated Research

Atmospheric-pressure plasma jets (APPJs) are currently being studied and developed for the biomedical, chemistry, and physics communities because of their ability to produce desirable reactive species at low temperatures and at atmospheric pressures. Due to the high particle densities, small scales, and nonequilibrium nature of these plasmas, they can be difficult to predict and compare across devices. In this article, a plasma jet is operated over a range of conditions and characterized by using optical emission spectroscopy (OES) and synchronized imaging. The effect of the operating conditions on the gas temperature, jet length, plasma formation, and reactive species produced is …


Experimental And Numerical Analysis Of Quasi-Static Deformation Mechanisms Of Additively Manufactured Lattice Structures, Behzad Bahrami Babamiri Sep 2019

Experimental And Numerical Analysis Of Quasi-Static Deformation Mechanisms Of Additively Manufactured Lattice Structures, Behzad Bahrami Babamiri

Von Braun Symposium Student Posters

No abstract provided.


Seeded Hydrogen In Nuclear Thermal Propulsion (Ntp) Engines, Daria Nikitaeva Sep 2019

Seeded Hydrogen In Nuclear Thermal Propulsion (Ntp) Engines, Daria Nikitaeva

Von Braun Symposium Student Posters

No abstract provided.


Evaluation Of Varying Surface Finishes On Thin-Walled Blown Powdered Deposition Inconel 625, Noah Naden, Giancarlo Puerto, Judy Schneider Sep 2019

Evaluation Of Varying Surface Finishes On Thin-Walled Blown Powdered Deposition Inconel 625, Noah Naden, Giancarlo Puerto, Judy Schneider

Von Braun Symposium Student Posters

No abstract provided.


Characterization Of A Pulse-Recharge Circuit For Puff, Nathan Schilling Sep 2019

Characterization Of A Pulse-Recharge Circuit For Puff, Nathan Schilling

Von Braun Symposium Student Posters

No abstract provided.


Design And Development Of An Autonomous Return Vehicle, Sean Widmier, An Nguyen, Colin Oberthur, Sean Mitchell, Fred Snopl Sep 2019

Design And Development Of An Autonomous Return Vehicle, Sean Widmier, An Nguyen, Colin Oberthur, Sean Mitchell, Fred Snopl

Von Braun Symposium Student Posters

No abstract provided.


Clustering Of Rapidly Settling, Low-Inertia Particle Pairs In Isotropic Turbulence. Part 2. Comparison Of Theory And Dns, Sarma L. Rani, Rohit Dhariwal, Donald L. Koch Jul 2019

Clustering Of Rapidly Settling, Low-Inertia Particle Pairs In Isotropic Turbulence. Part 2. Comparison Of Theory And Dns, Sarma L. Rani, Rohit Dhariwal, Donald L. Koch

PRC-Affiliated Research

Part 1 (Rani et al. J. Fluid Mech. , vol. 871, 2019, pp. 450–476) of this study presented a stochastic theory for the clustering of monodisperse, rapidly settling, low-Stokes-number particle pairs in homogeneous isotropic turbulence. The theory involved the development of closure approximations for the drift and diffusion fluxes in the probability density function (p.d.f.) equation for the pair relative positions $\boldsymbol{r}$ . In this part 2 paper, the theory is quantitatively analysed by comparing its predictions of particle clustering with data from direct numerical simulations (DNS) of isotropic turbulence containing particles settling under gravity. The simulations were performed at …


Clustering Of Rapidly Settling, Low-Inertia Particle Pairs In Isotropic Turbulence. Part 1. Drift And Diffusion Flux Closures, Sarma L. Rani, Vijay K. Gupta, Donald L. Koch Jul 2019

Clustering Of Rapidly Settling, Low-Inertia Particle Pairs In Isotropic Turbulence. Part 1. Drift And Diffusion Flux Closures, Sarma L. Rani, Vijay K. Gupta, Donald L. Koch

PRC-Affiliated Research

In this two-part study, we present the development and analysis of a stochastic theory for characterizing the relative positions of monodisperse, low-inertia particle pairs that are settling rapidly in homogeneous isotropic turbulence. In the limits of small Stokes number and Froude number such that , closures are developed for the drift and diffusion fluxes in the probability density function (p.d.f.) equation for the pair relative positions. The theory focuses on the relative motion of particle pairs in the dissipation regime of turbulence, i.e. for pair separations smaller than the Kolmogorov length scale. In this regime, the theory approximates the fluid …


Clustering Of Rapidly Settling, Low-Inertia Particle Pairs In Isotropic Turbulence. Part 1. Drift And Diffusion Flux Closures, Sarma L. Rani, Vijay K. Gupta, Donald L. Koch Jul 2019

Clustering Of Rapidly Settling, Low-Inertia Particle Pairs In Isotropic Turbulence. Part 1. Drift And Diffusion Flux Closures, Sarma L. Rani, Vijay K. Gupta, Donald L. Koch

PRC-Affiliated Research

In this two-part study, we present the development and analysis of a stochastic theory for characterizing the relative positions of monodisperse, low-inertia particle pairs that are settling rapidly in homogeneous isotropic turbulence. In the limits of small Stokes number and Froude number such that , closures are developed for the drift and diffusion fluxes in the probability density function (p.d.f.) equation for the pair relative positions. The theory focuses on the relative motion of particle pairs in the dissipation regime of turbulence, i.e. for pair separations smaller than the Kolmogorov length scale. In this regime, the theory approximates the fluid …


Clustering Of Rapidly Settling, Low-Inertia Particle Pairs In Isotropic Turbulence. Part 2. Comparison Of Theory And Dns, Sarma L. Rani, Rohit Dhariwal, Donald L. Koch Jul 2019

Clustering Of Rapidly Settling, Low-Inertia Particle Pairs In Isotropic Turbulence. Part 2. Comparison Of Theory And Dns, Sarma L. Rani, Rohit Dhariwal, Donald L. Koch

PRC-Affiliated Research

Part 1 (Rani et al. J. Fluid Mech. , vol. 871, 2019, pp. 450–476) of this study presented a stochastic theory for the clustering of monodisperse, rapidly settling, low-Stokes-number particle pairs in homogeneous isotropic turbulence. The theory involved the development of closure approximations for the drift and diffusion fluxes in the probability density function (p.d.f.) equation for the pair relative positions $\boldsymbol{r}$ . In this part 2 paper, the theory is quantitatively analysed by comparing its predictions of particle clustering with data from direct numerical simulations (DNS) of isotropic turbulence containing particles settling under gravity. The simulations were performed at …


Clustering Of Rapidly Settling, Low-Inertia Particle Pairs In Isotropic Turbulence. Part 1. Drift And Diffusion Flux Closures, Sarma L. Rani, Vijay K. Gupta, Donald L. Koch Jul 2019

Clustering Of Rapidly Settling, Low-Inertia Particle Pairs In Isotropic Turbulence. Part 1. Drift And Diffusion Flux Closures, Sarma L. Rani, Vijay K. Gupta, Donald L. Koch

PRC-Affiliated Research

In this two-part study, we present the development and analysis of a stochastic theory for characterizing the relative positions of monodisperse, low-inertia particle pairs that are settling rapidly in homogeneous isotropic turbulence. In the limits of small Stokes number and Froude number such that , closures are developed for the drift and diffusion fluxes in the probability density function (p.d.f.) equation for the pair relative positions. The theory focuses on the relative motion of particle pairs in the dissipation regime of turbulence, i.e. for pair separations smaller than the Kolmogorov length scale. In this regime, the theory approximates the fluid …


Clustering Of Rapidly Settling, Low-Inertia Particle Pairs In Isotropic Turbulence. Part 2. Comparison Of Theory And Dns, Sarma L. Rani, Rohit Dhariwal, Donald L. Koch Jul 2019

Clustering Of Rapidly Settling, Low-Inertia Particle Pairs In Isotropic Turbulence. Part 2. Comparison Of Theory And Dns, Sarma L. Rani, Rohit Dhariwal, Donald L. Koch

PRC-Affiliated Research

Part 1 (Rani et al. J. Fluid Mech. , vol. 871, 2019, pp. 450–476) of this study presented a stochastic theory for the clustering of monodisperse, rapidly settling, low-Stokes-number particle pairs in homogeneous isotropic turbulence. The theory involved the development of closure approximations for the drift and diffusion fluxes in the probability density function (p.d.f.) equation for the pair relative positions $\boldsymbol{r}$ . In this part 2 paper, the theory is quantitatively analysed by comparing its predictions of particle clustering with data from direct numerical simulations (DNS) of isotropic turbulence containing particles settling under gravity. The simulations were performed at …


2019 Spring Graduate Recognition Program, Propulsion Research Center, Robert Frederick May 2019

2019 Spring Graduate Recognition Program, Propulsion Research Center, Robert Frederick

PRC Graduate Recognition

This program includes the graduate recognition program for spring 2019. Includes photographs, upcoming events, recent publications, and student profiles.


Double Wall Cooling Of A Full Coverage Effusion Plate With Main Flow Pressure Gradient, Including Internal Impingement Array Cooling, Sneha R. Vanga, David Ritchie, Austin Click, Zhong Ren, Phil Ligrani, Federico Liberatore, Rajeshriben Patel, Ram Srinivasan, Yin-Hsiang Ho Apr 2019

Double Wall Cooling Of A Full Coverage Effusion Plate With Main Flow Pressure Gradient, Including Internal Impingement Array Cooling, Sneha R. Vanga, David Ritchie, Austin Click, Zhong Ren, Phil Ligrani, Federico Liberatore, Rajeshriben Patel, Ram Srinivasan, Yin-Hsiang Ho

PRC-Affiliated Research

The present study provides new effusion cooling data for both the surfaces of the fullcoverage effusion cooling plate. For the effusion-cooled surface, presented are spatially resolved distributions of surface adiabatic film cooling effectiveness and surface heat transfer coefficients (measured using transient techniques and infrared thermography). For the impingement-cooled surface, presented are spatially resolved distributions of surface Nusselt numbers (measured using steady-state liquid crystal thermography). To produce this cool-side augmentation, impingement jet arrays at different jet Reynolds numbers, from 2720 to 11,100, are employed. Experimental data are given for a sparse effusion hole array, with spanwise and streamwise impingement hole spacing …


Double Wall Cooling Of A Full Coverage Effusion Plate With Main Flow Pressure Gradient, Including Internal Impingement Array Cooling, Sneha R. Vanga, David Ritchie, Austin Click, Zhong Ren, Phil Ligrani, Federico Liberatore, Rajeshriben Patel, Ram Srinivasan, Yin-Hsiang Ho Apr 2019

Double Wall Cooling Of A Full Coverage Effusion Plate With Main Flow Pressure Gradient, Including Internal Impingement Array Cooling, Sneha R. Vanga, David Ritchie, Austin Click, Zhong Ren, Phil Ligrani, Federico Liberatore, Rajeshriben Patel, Ram Srinivasan, Yin-Hsiang Ho

PRC-Affiliated Research

The present study provides new effusion cooling data for both the surfaces of the fullcoverage effusion cooling plate. For the effusion-cooled surface, presented are spatially resolved distributions of surface adiabatic film cooling effectiveness and surface heat transfer coefficients (measured using transient techniques and infrared thermography). For the impingement-cooled surface, presented are spatially resolved distributions of surface Nusselt numbers (measured using steady-state liquid crystal thermography). To produce this cool-side augmentation, impingement jet arrays at different jet Reynolds numbers, from 2720 to 11,100, are employed. Experimental data are given for a sparse effusion hole array, with spanwise and streamwise impingement hole spacing …


Double Wall Cooling Of A Full Coverage Effusion Plate With Main Flow Pressure Gradient, Including Internal Impingement Array Cooling, Sneha R. Vanga, David Ritchie, Austin Click, Zhong Ren, Phil Ligrani, Federico Liberatore, Rajeshriben Patel, Ram Srinivasan, Yin-Hsiang Ho Apr 2019

Double Wall Cooling Of A Full Coverage Effusion Plate With Main Flow Pressure Gradient, Including Internal Impingement Array Cooling, Sneha R. Vanga, David Ritchie, Austin Click, Zhong Ren, Phil Ligrani, Federico Liberatore, Rajeshriben Patel, Ram Srinivasan, Yin-Hsiang Ho

PRC-Affiliated Research

The present study provides new effusion cooling data for both the surfaces of the fullcoverage effusion cooling plate. For the effusion-cooled surface, presented are spatially resolved distributions of surface adiabatic film cooling effectiveness and surface heat transfer coefficients (measured using transient techniques and infrared thermography). For the impingement-cooled surface, presented are spatially resolved distributions of surface Nusselt numbers (measured using steady-state liquid crystal thermography). To produce this cool-side augmentation, impingement jet arrays at different jet Reynolds numbers, from 2720 to 11,100, are employed. Experimental data are given for a sparse effusion hole array, with spanwise and streamwise impingement hole spacing …


Nuclear Thermal Propulsion Reactor Shutdown And Residual Heating, Samantha B. Rawlins Mar 2019

Nuclear Thermal Propulsion Reactor Shutdown And Residual Heating, Samantha B. Rawlins

Research Horizons Day Posters

No abstract provided.


Development Of A Magnetic Nozzle Model For Puff, Nathan Schilling Mar 2019

Development Of A Magnetic Nozzle Model For Puff, Nathan Schilling

Research Horizons Day Posters

No abstract provided.


Rotor Wing Interaction Of The Low Reynolds Numbers, Darnisha Crane, Mingtai Chen Mar 2019

Rotor Wing Interaction Of The Low Reynolds Numbers, Darnisha Crane, Mingtai Chen

Research Horizons Day Posters

No abstract provided.