Open Access. Powered by Scholars. Published by Universities.®
- Institution
- Keyword
-
- Compressible turbulence (2)
- Turbulent boundary layers (2)
- Adverse elevator effect (1)
- Airplanes (1)
- Blast (1)
-
- Boil (1)
- Boussinesq (1)
- Bubble dynamics (1)
- Capacity planning (1)
- Contamination (1)
- Control Systems (1)
- Control with constraints; Sliding modes; Hybrid systems; Aircraft engines; Selector systems (1)
- DNS and LES Simulations (1)
- Discrete event simulation (1)
- Experiment (1)
- Facility layout design (1)
- Facility planning (1)
- Fiber Sensors (1)
- Fiso (1)
- Flare (1)
- Fluid interactions (1)
- GAS (1)
- Geophysical Flows (1)
- Getaway Special (1)
- Grain terminal (1)
- Gravity (1)
- Heat flux (1)
- High-speed flow (1)
- LabVIEW (1)
- Landing (1)
- Publication
-
- Mechanical and Aerospace Engineering Faculty Research & Creative Works (13)
- Presentations (4)
- Aviation Department Publications (2)
- Education and Outreach (2)
- Electrical and Computer Engineering Faculty Research & Creative Works (2)
-
- Reports and Proposals (2)
- Department of Engineering Mechanics: Dissertations, Theses, and Student Research (1)
- Department of Industrial and Management Systems Engineering: Dissertations, Theses, and Student Research (1)
- Masters Theses 1911 - February 2014 (1)
- Mechanical Engineering Faculty Publications (1)
- File Type
Articles 1 - 29 of 29
Full-Text Articles in Mechanical Engineering
Effect Of Thin Film Confined Between Two Dissimilar Solids On Interfacial Thermal Resistance, Zhi Liang, Hai-Lung Tsai
Effect Of Thin Film Confined Between Two Dissimilar Solids On Interfacial Thermal Resistance, Zhi Liang, Hai-Lung Tsai
Mechanical and Aerospace Engineering Faculty Research & Creative Works
A Non-Equilibrium Molecular Dynamics Model is Developed to Investigate How a Thin Film Confined between Two Dissimilar Solids Affects the Thermal Transport Across the Material Interface. for Two Highly Dissimilar (Phonon Frequency Mismatched) Solids, It is Found that the Insertion of a Thin Film between Them Can Greatly Enhance Thermal Transport Across the Material Interface by a Factor of 2.3 If the Thin Film Has One of the Following Characteristics: (1)a Multi-Atom-Thick Thin Film of Which the Phonon Density of States (DOS) Bridges the Two Different Phonon DOSs for the Solid on Each Side of the Thin Film; (2)a Single-Atom-Thick …
Direct Numerical Simulation Of Hypersonic Turbulent Boundary Layers. Part 4. Effect Of High Enthalpy, L. (Lian) Duan, M. P. Martín
Direct Numerical Simulation Of Hypersonic Turbulent Boundary Layers. Part 4. Effect Of High Enthalpy, L. (Lian) Duan, M. P. Martín
Mechanical and Aerospace Engineering Faculty Research & Creative Works
In this paper we present direct numerical simulations (DNS) of hypersonic turbulent boundary layers to study high-enthalpy effects. We study high-and low-enthalpy conditions, which are representative of those in hypersonic flight and ground-based facilities, respectively. We find that high-enthalpy boundary layers closely resemble those at low enthalpy. Many of the scaling relations for low-enthalpy flows, such as van-Driest transformation for the mean velocity, Morkovin's scaling, and the modified strong Reynolds analogy hold or can be generalized for high-enthalpy flows by removing the calorically perfect-gas assumption. We propose a generalized form of the modified Crocco relation, which relates the mean temperature …
A Multi-Regulator Sliding Mode Control Strategy For Output-Constrained Systems, Hanz Richter
A Multi-Regulator Sliding Mode Control Strategy For Output-Constrained Systems, Hanz Richter
Mechanical Engineering Faculty Publications
This paper proposes a multi-regulator control scheme for single-input systems, where the setpoint of a regulated output must be changed under the constraint that a set of minimum-phase outputs remain within prescribed bounds. The strategy is based on a max–min selector system frequently used in the aerospace field. The regulators used for the regulated and limited outputs are of the sliding mode type, where the sliding variable is defined as the difference between an output and its allowable limit. The paper establishes overall asymptotic stability, as well as invariance properties leading to limit protection. The design methodology is illustrated with …
Effective Approach For Estimating Turbulence-Chemistry Interaction In Hypersonic Turbulent Boundary Layers, L. (Lian) Duan, M. P. Martín
Effective Approach For Estimating Turbulence-Chemistry Interaction In Hypersonic Turbulent Boundary Layers, L. (Lian) Duan, M. P. Martín
Mechanical and Aerospace Engineering Faculty Research & Creative Works
An effective approach for estimating turbulence-chemistry interaction in hypersonic turbulent boundary layers is proposed, based on "laminar- chemistry" Reynolds-averaged Navier-Stokes mean flow solutions. The approach combines an assumed probability density function with a temperature fluctuation scaling, which provides the second moment for specifying the shape of the probability density function. As a result, the effects of temperature fluctuation on chemical production rates can be estimated without solving an additional moment evolution equation. The validity of this method is demonstrated using direct-numerical-simulation data. This approach can be used to identify regions with potentially significant turbulence-chemistry interaction in hypersonic boundary layers and …
Effect Of The Thickness Of Undoped Gan Interlayers Between Multiple Quantum Wells And The P-Doped Layer On The Performance Of Gan Light-Emitting Diodes, T. Lu, S. Li, K. Zhang, C. Liu, Y. Yin, L. Wu, H. Wang, Xiaodong Yang, G. Xiao, Y. Zhou
Effect Of The Thickness Of Undoped Gan Interlayers Between Multiple Quantum Wells And The P-Doped Layer On The Performance Of Gan Light-Emitting Diodes, T. Lu, S. Li, K. Zhang, C. Liu, Y. Yin, L. Wu, H. Wang, Xiaodong Yang, G. Xiao, Y. Zhou
Mechanical and Aerospace Engineering Faculty Research & Creative Works
InGaN based light-emitting diodes (LEDs) with undoped GaN interlayer of variant thicknesses grown by metal-organic chemical vapor deposition technique have been investigated. It was found that the thickness of undoped GaN interlayers affected LEDs' performance greatly. The LED with 50 nm undoped GaN interlayer showed higher light output power and lower reverse-leakage current compared with the others at 20 mA. Based on electrical and optical characteristics analysis and numerical simulation, these improvements are mainly attributed to the improvement of the quality of depletion region by inserting an undoped GaN layer, as well as reduction of the Shockley-Read-Hall recombination in InGaN/GaN …
Thermal Expansions In Wurtzite Aln, Gan, And Inn: First-Principle Phonon Calculations, L.-C. Xu, R.-Z. Wang, Xiaodong Yang, H. Yan
Thermal Expansions In Wurtzite Aln, Gan, And Inn: First-Principle Phonon Calculations, L.-C. Xu, R.-Z. Wang, Xiaodong Yang, H. Yan
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Using the first-principle phonon calculations under the quasiharmonic approximation, thermal expansions in III-nitrides with wurtzite AlN, GaN, and InN are reported. The results showed that it is different for each thermal expansion of three III-nitrides at low temperatures, which is consistent with their Grneisen parameters as the function of temperature. Below 50 K, negative thermal expansions occur in InN, while GaN and AlN follow the rule of positive thermal expansion. To seek the origin of positivenegative thermal expansion distinction, the mode Grneisen parameters and the phonon spectra are investigated. They indicate that different low-frequency phonon vibration modes correspond to the …
Astro Camp Presentation, Get Away Special Team 2011
Astro Camp Presentation, Get Away Special Team 2011
Education and Outreach
No abstract provided.
A Study On Facility Planning Using Discrete Event Simulation: Case Study Of A Grain Delivery Terminal., Sarah M. Asio
A Study On Facility Planning Using Discrete Event Simulation: Case Study Of A Grain Delivery Terminal., Sarah M. Asio
Department of Industrial and Management Systems Engineering: Dissertations, Theses, and Student Research
The application of traditional approaches to the design of efficient facilities can be tedious and time consuming when uncertainty and a number of constraints exist. Queuing models and mathematical programming techniques are not able to capture the complex interaction between resources, the environment and space constraints for dynamic stochastic processes. In the following study discrete event simulation is applied to the facility planning process for a grain delivery terminal. The discrete event simulation approach has been applied to studies such as capacity planning and facility layout for a gasoline station and evaluating the resource requirements for a manufacturing facility. To …
Effect Of Molecular Film Thickness On Thermal Conduction Across Solid-Film Interfaces, Zhi Liang, Hai-Lung Tsai
Effect Of Molecular Film Thickness On Thermal Conduction Across Solid-Film Interfaces, Zhi Liang, Hai-Lung Tsai
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The Brownian Motion and Aggregation of Particles in Nanofluids Often Lead to the Formation of Solid-Film-Solid Structures. the Molecular Thin Film Confined between Nanoparticles May Have Non-Negligible Effects on Thermal Conduction among Nanoparticles. using Nonequilibrium Molecular Dynamics Simulations, We Study Thermal Conduction Across the Ag Particle-Ar Thin-Film Interface. If the Film Contains Only One Molecular Layer, We Find that the Solid-Film Interfacial Thermal Resistance RSF is About 1 Order of Magnitude Smaller Than the Solid-Liquid (Bulk) Interfacial Thermal Resistance RSL. If There Are Two or More Molecular Layers in the Film, It is Shown that RSF Increases Rapidly toward RSL …
Airplane Landing Flare-The Last 5 Seconds, Nihad E. Daidzic
Airplane Landing Flare-The Last 5 Seconds, Nihad E. Daidzic
Aviation Department Publications
No abstract provided.
Direct Numerical Simulation Of Hypersonic Turbulent Boundary Layers. Part 3. Effect Of Mach Number, L. (Lian) Duan, I. Beekman, M. P. Martín
Direct Numerical Simulation Of Hypersonic Turbulent Boundary Layers. Part 3. Effect Of Mach Number, L. (Lian) Duan, I. Beekman, M. P. Martín
Mechanical and Aerospace Engineering Faculty Research & Creative Works
In this paper, we perform direct numerical simulations (DNS) of turbulent boundary layers with nominal free-stream Mach number ranging from 0.3 to 12. The main objective is to assess the scaling's with respect to the mean and turbulence behaviors as well as the possible breakdown of the weak compressibility hypothesis for turbulent boundary layers at high Mach numbers (M > 5). We find that many of the scaling relations, such as the van Driest transformation for mean velocity, Walz's relation, Morkovin's scaling and the strong Reynolds analogy, which are derived based on the weak compressibility hypothesis, remain valid for the range …
Surface Geometry And Heat Flux Effect On Thin Wire Nucleate Pool Boiling Of Subcooled Water In Mictrogravity, Troy Munro, Heng Ban
Surface Geometry And Heat Flux Effect On Thin Wire Nucleate Pool Boiling Of Subcooled Water In Mictrogravity, Troy Munro, Heng Ban
Presentations
No abstract provided.
Thermal Conductivity Of Interfacial Layers In Nanofluids, Zhi Liang, Hai-Lung Tsai
Thermal Conductivity Of Interfacial Layers In Nanofluids, Zhi Liang, Hai-Lung Tsai
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Thermal Conductivity of Interfacial Layers is an Essential Parameter for Determining How the Ordered Liquid Layering Around the Particle-Liquid Interface Contributes to the Unusual High Thermal Conductivity of Nanofluids. However, So Far There is No Experimental Data Regarding This Parameter. using Nonequilibrium Molecular Dynamics Simulations of an Inhomogeneous Au-Ar System in Which the Solid-Liquid Interactions Are Assumed to Be Much Stronger Than the Liquid-Liquid Interactions, We Show Explicitly that the Thermal Conductivity of a 1-Nm-Thick Interfacial Layer is 1.6∼2.5 Times Higher Than that of the Base Fluid. the Simulation Results Are Incorporated into a Three-Level Clustering Model to Calculate the …
Some Considerations For Regional Airline Operations On Contaminated Runways., Nihad E. Daidzic
Some Considerations For Regional Airline Operations On Contaminated Runways., Nihad E. Daidzic
Aviation Department Publications
No abstract provided.
Surface Geometry And Heat Flux Effect On Thin Wire Nucleate Pool Boiling Of Subcooled Water In Microgravity, Troy Munro, Andrew Fassman
Surface Geometry And Heat Flux Effect On Thin Wire Nucleate Pool Boiling Of Subcooled Water In Microgravity, Troy Munro, Andrew Fassman
Presentations
The motivation of this nucleate boiling research is to understand the effects of surface geometry and heat flux as applied to a thin wire heater. This will further the understanding of the fundamental behaviors of boiling onset, steady state heat transfer, and bubble dynamics with respect to nucleate boiling with the goal of creating efficient thermal management systems for future space applications. Using three different thin platinum wire geometries and five different power levels, subcooled water was boiled over a period of approximately 30 seconds for 15 parabolic arcs to simulate microgravity. To represent the trends in bubbles behavior across …
Deterministic Integrated Tuning Of Multicavity Resonances And Phase For Slow-Light In Coupled Photonic Crystal Cavities, T. Gu, S. Kocaman, Xiaodong Yang, J. F. Mcmillan, M. B. Yu, G.-Q. Lo, D.-L. Kwong, C. W. Wong
Deterministic Integrated Tuning Of Multicavity Resonances And Phase For Slow-Light In Coupled Photonic Crystal Cavities, T. Gu, S. Kocaman, Xiaodong Yang, J. F. Mcmillan, M. B. Yu, G.-Q. Lo, D.-L. Kwong, C. W. Wong
Mechanical and Aerospace Engineering Faculty Research & Creative Works
We present the integrated chip-scale tuning of multiple photonic crystal cavities. The optimized implementation allows effective and precise tuning of multiple cavity resonances (up to ~1.60 nm/mW) and intercavity phase (~0.038 π/mW) by direct local temperature tuning on suspended silicon nanomembranes. Through designing the serpentine metal electrodes and careful electron-beam alignment to avoid cavity mode overlap, the coupled photonic crystal L3 cavities preserve their high quality factors. The deterministic resonance and phase control enables switching between the all-optical analog of electromagnetically-induced-transparency to flat-top filter lineshapes, with future applications of trapping photons and optoelectronic modulators.
Effects Of Heat Flux On Nucleate Boiling In Microgravity, Andrew Fassman
Effects Of Heat Flux On Nucleate Boiling In Microgravity, Andrew Fassman
Presentations
No abstract provided.
The Design And Construction Of A Microgravity Boiling Experiment, Troy Munro
The Design And Construction Of A Microgravity Boiling Experiment, Troy Munro
Presentations
No abstract provided.
Nanostructured Substrate With Nanoparticles Fabricated By Femtosecond Laser For Surface-Enhanced Raman Scattering, Yukun Han, Zhi Liang, Huilai Sun, Hai Xiao, Hai-Lung Tsai
Nanostructured Substrate With Nanoparticles Fabricated By Femtosecond Laser For Surface-Enhanced Raman Scattering, Yukun Han, Zhi Liang, Huilai Sun, Hai Xiao, Hai-Lung Tsai
Electrical and Computer Engineering Faculty Research & Creative Works
A Simple and Fast Method to Fabricate Nanostructured Substrates with Silver Nanoparticles over a Large Area for Surface-Enhanced Raman Scattering (SERS) is Reported. the Method Involves Two Steps: (1) Dip the Substrate into a Silver Nitrate Solution for a Few Minutes, Remove the Substrate from the Solution, and Then Air Dry and (2) Process the Silver Nitrate Coated Substrate by Femtosecond (Fs) Laser Pulses in Air. the Second Step Can Create Silver Nanoparticles Distributed on the Nanostructured Surface of the Substrate by the Photoreduction of Fs Multiphoton Effects. This Study Demonstrates that an Enhancement Factor (EF) Greater Than 5x105, Measured …
Study Of Emission Turbulence-Radiation Interaction In Hypersonic Boundary Layers, L. (Lian) Duan, M. P. Martín, I. Sohn, D. A. Levin, M. F. Modest
Study Of Emission Turbulence-Radiation Interaction In Hypersonic Boundary Layers, L. (Lian) Duan, M. P. Martín, I. Sohn, D. A. Levin, M. F. Modest
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Direct numerical simulations are conducted to study the effects of emission turbulence-radiation interaction in hypersonic turbulent boundary layers, representative of the Orion Crew Exploration Vehicle at peak-heating condition during reentry. A nondimensional governing parameter to measure the significance of emission turbulence-radiation interaction is proposed, and the direct numerical simulation fields with and without emission coupling are used to assess emission turbulence-radiation interaction. Both the uncoupled and coupled results show that there is no sizable interaction between turbulence and emission at the hypersonic environment under investigation. An explanation of why the intensity of emission turbulence-radiation interaction in the hypersonic boundary layer …
Numerical Forcing Of Horizontally-Homogeneous Stratified Turbulence, Kaustubh J. Rao
Numerical Forcing Of Horizontally-Homogeneous Stratified Turbulence, Kaustubh J. Rao
Masters Theses 1911 - February 2014
It is often desirable to study simulated turbulent flows at steady state even if the flow has no inherent source of turbulence kinetic energy. Doing so requires a numerical forcing scheme and various methods have been studied extensively for turbulence that is isotropic and homogeneous in three dimensions. A review of these existing schemes is used to form a framework for more general forcing methods. In this framework, the problem of developing a forcing scheme in Fourier space is abstracted into the two problems of (1) prescribing the spectrum of the input power and (2) specifying a force that has …
Get Away Special: Microgravity Research Team, Getaway Special Team
Get Away Special: Microgravity Research Team, Getaway Special Team
Education and Outreach
No abstract provided.
Report For 2011 Urco Funded Experiment: Development Of Optimal Bubble-Seeding Microheaters To Study Nucleate Boiling Heat Transfer In Microgravity, Ryan Martineau
Reports and Proposals
No abstract provided.
Development Of Optimal Bubble-Seeding Microheaters To Study Nucleate Boiling Heat Transfer In Microgravity, Ryan Martineau
Development Of Optimal Bubble-Seeding Microheaters To Study Nucleate Boiling Heat Transfer In Microgravity, Ryan Martineau
Reports and Proposals
No abstract provided.
Assessment Of Turbulence-Chemistry Interaction In Hypersonic Turbulent Boundary Layers, L. (Lian) Duan, M. P. Martín
Assessment Of Turbulence-Chemistry Interaction In Hypersonic Turbulent Boundary Layers, L. (Lian) Duan, M. P. Martín
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Studies of the turbulence-chemistry interaction are performed in hypersonic turbulent boundary layers using direct numerical simulation flow fields under typical hypersonic conditions representative of blunt-body and slender body hypersonic vehicles, with super catalytic and noncatalytic wall conditions in pure air. Nondimensional governing parameters, the interaction Damköhler number and the interaction relative heat release, are proposed to measure the influence of turbulence-chemistry interaction on flow composition and temperature. Both a priori and posteriori studies are performed to assess the effect of turbulence-chemistry interaction on chemical production rates and mean and turbulent flow characteristics. It is found that the governing parameters provide …
Study Of Turbulence-Chemistry Interaction In Hypersonic Turbulent Boundary Layers, Lian Duan, M. Pino Martín
Study Of Turbulence-Chemistry Interaction In Hypersonic Turbulent Boundary Layers, Lian Duan, M. Pino Martín
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Studies of the turbulence-chemistry interaction (TCI) are performed in hypersonic turbulent boundary layers using direct numerical simulation (DNS) flow fields under typical hypersonic conditions representative of blunt-body and slender-body hypersonic vehicles, with super catalytic and noncatalytic wall conditions in pure air. Nondimensional governing parameters, 'interaction' Damk̈ohler number and relative heat release, are proposed to measure the influence of TCI on flow composition and temperature. Both a priori and posteriori studies are performed to assess the effect of TCI on chemical production rates and mean and turbulence flow characteristics. In addition, an effective approach (called PDF-TS) to estimate the intensity of …
Study Of Turbulence-Radiation Interaction In Hypersonic Turbulent Boundary Layers, L. (Lian) Duan, A. M. Feldick, M. P. Martín, M. F. Modest, D. A. Levin
Study Of Turbulence-Radiation Interaction In Hypersonic Turbulent Boundary Layers, L. (Lian) Duan, A. M. Feldick, M. P. Martín, M. F. Modest, D. A. Levin
Mechanical and Aerospace Engineering Faculty Research & Creative Works
In the paper, we conduct direct numerical simulations (DNS) to investigate the effect of turbulence-radiation interaction (TRI) in hypersonic turbulent boundary layers, representative of the Orion crew exploration vehicle (CEV) at peak heating condition during reentry. The radiative transfer equation (RTE) is solved using the tangent slab approximation. 1 The RTE solver is line-by-line (LBL) accurate, making use of a developed efficient spectral database 2 for spectral modeling. A multi-group full-spectrum correlated-k-distribution (FSCK) method 3 is used to reduce the number of RTE evaluations while preserving LBL accuracy. A nondimensional governing parameter to measure the significance of TRI is proposed, …
Ultra-Abrupt Tapered Fiber Mach-Zehnder Interferometer Sensors, B. Li, J. Lan, W. Sumei, L. Zhou, Hai Xiao, Hai-Lung Tsai
Ultra-Abrupt Tapered Fiber Mach-Zehnder Interferometer Sensors, B. Li, J. Lan, W. Sumei, L. Zhou, Hai Xiao, Hai-Lung Tsai
Electrical and Computer Engineering Faculty Research & Creative Works
A fiber inline Mach-Zehnder interferometer (MZI) consisting of ultra-abrupt fiber tapers was fabricated through a new fusion-splicing method. By fusion-splicing, the taper diameter-length ratio is around 1:1, which is much greater than those (1:10) made by stretching. The proposed fabrication method is very low cost, 1/20-1/50 of those of LPFG pair MZI sensors. The fabricated MZIs are applied to measure refractive index, temperature and rotation angle changes. The temperature sensitivity of the MZI at a length of 30 mm is 0.061 nm/°C from 30-350 °C. The proposed MZI is also used to measure rotation angles ranging from 0° to 0.55°; …
A Shock Tube Technique For Blast Wave Simulation And Studies Of Flow Structure Interactions In Shock Tube Blast Experiments, Nicholas N. Kleinschmit
A Shock Tube Technique For Blast Wave Simulation And Studies Of Flow Structure Interactions In Shock Tube Blast Experiments, Nicholas N. Kleinschmit
Department of Engineering Mechanics: Dissertations, Theses, and Student Research
Improvised explosive devices (IED’s) are widely used against US and allied forces fighting in Iraq and Afghanistan. Exposure to IED blast may cause blast-induced traumatic brain injury (bTBI). The injury mechanisms are however not well understood. A critical need in bTBI-related research is the ability to replicate the loading conditions of IED blast waves in a laboratory environment. In this work, experimental studies have been carried out to explore the use of the shock tube technique for generating air shock waves that mimic the temporal and spatial characteristics of free-field blast waves and to investigate the blast wave-test sample interactions …