This thesis uses numerical simulation to study a new communication method for addressing radio blackout during hypersonic flight. The radio blackout problem is an important issue for hypersonic vehicles because of flight safety, catastrophe analysis, and mission success. During the last 50 years, several approaches have been proposed to solve radio blackout. However, from the …
Tag Archive: FluidandPlasma
Feb
23
34 GHz second-harmonic peniotron oscillator
Harmonic operation of gyro-devices has been proposed as a way to lower the magnetic field required to a level feasible with normal i.e., non-superconducting) magnets. The problem is, however, that gyrotron efficiency drops dramatically at harmonics greater than two, making development of such a device of limited utility. A promising solution to this quandary is …
Feb
22
Studies of plasma diagnostics for carbon nanotube growth with plasma enhanced chemical vapor deposition
In this study, various plasma diagnostics were used to determine which gas-phase species were present under conditions that were favorable for plasma-enhanced chemical vapor deposition PECVD) growth of carbon nanotubes on metal catalysts. The nature of the deposited material and the identification and relative concentrations of species were determined as a function of varying pressures, …
Feb
19
A Study of Quantitative Concentrations of Hydroxyl (OH) in Laminar Flat Flames Using Planar Laser Induced Fluorescence (PLIF)
In these times of striving for cleaner, more efficient fuels, research is needed to provide understanding that will allow technologies to improve. Planar laser induced fluorescence PLIF) is a popular, non-intrusive technique for studying flame structure. A radical species, hydroxyl OH), is known to be found in the region between burned and unburned gases in …
Feb
17
Computational study of arc discharges: Spark plug and railplug ignitors
A theoretical study of electrical arc discharges that focuses on the discharge processes in spark plug and railplug ignitors is presented. The aim of the study is to gain a better understanding of the dynamics of electrical discharges, more specifically the transfer of electrical energy into the gas and the effect of this energy transfer …
Feb
16
Nonlinear Phenomena of Plasma Waves in a Kinetic Regime: Frequency Shifts, Packets, and Transverse Localization
The generation and propagation of nonlinear plasma waves is studied using particle-in-cell (PIC) simulations. We concentrate on regimes of interest to inertial fusion and space physics in which wave-particle interactions are important. Experiments soon to be performed at the National Ignition Facility require the understanding and control of stimulated Raman scattering (SRS) for their success. …
Feb
14
Modeling Earth’s Outer Radiation Belt Electron Dynamics—Radial Diffusion, Heating, and Loss
Earths outer radiation belt is a relativistic electron environment that is hazardous to space systems. It is characterized by large variations in the electron flux, which are controlled by the competition between source, transport, and loss processes. One of the central questions in outer radiation belt research is to resolve the relative contribution of radial …
Feb
13
Application of experimental and numerical simulation techniques to microscale devices
Two of the areas that have become relevant recently are the areas of mixing in micro-scale devices, and manufacturing of functional nanoparticles. MicroPIV experiments were performed on two different mixers, one a wide microchannel with the surface grooves, in the laminar regime, and the other, a confined impinging jets reactor, in the laminar and turbulent …
Feb
12
Incorporation of an energy equation into a pulsed inductive plasma acceleration model
Electric propulsion systems utilize electrical energy to produce thrust for spacecraft propulsion. These systems have multiple applications ranging from Earth orbit North-South station keeping to solar system exploratory missions such as NASA’s Discovery, New Frontiers, and Flagship class missions that focus on exploring scientifically interesting targets. In an electromagnetic thruster, a magnetic field interacting with …
Feb
11
Three-Dimensional Numerical Simulations of Liquid Laminar Flow over Superhydrophobic Surfaces with Post Geometries
Frictional resistance reduction of liquid flow over surfaces has recently become a more important topic of research in the field of fluid dynamics. Scientific and technological progress and continued interest in nano and micro-technology have required new developments and approaches related to reducing frictional resistance, especially in liquid flow through nano and micro-channels. The application …