Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 44 for “"pressure waves"”.
-
The effects of pressure waves on turbulent oblique shock wave boundary layer interactions in rectangular channels
… increased turbulent fluctuations, and pressure losses. They often occur near to a side-wall, such as in rectangular intakes, which introduces a side-wall boundary layer. At the intersection of the primary surface and the side-wall, a thick corner boundary layer is formed containing low …
-
A Dynamical Study of the Evolution of Pressure Waves Propagating through a Semi-Infinite Region of Homogeneous Gas Combustion Subject to a Time-Harmonic Signal at the Boundary
<p>In this dissertation, the evolution of a pressure wave driven by a harmonic signal on the boundary during gas combustion is studied. The problem is modeled by a nonlinear, hyperbolic partial differential equation. Steady-state behavior is investigated using the perturbation method to ensure that …
-
Development of guidelines for exhaust system design from fundamental gas dynamics studies
… exhaust system geography, the exhaust port pressure history and the gas exchange process in reciprocating four-stroke engines. The study was conducted in four phases. In the first phase, an extensive experimental programme was undertaken, during which key engine performance indicators …
-
Psychoacoustic Entropy Theory and Its Implications for Performance Practice
… perceives instantaneous disorder within a sound pressure wave. Chapter one explains the importance of harmonic analysis as a tool for performance practice. It also outlines the critical limitations for many of the most influential historical approaches to modeling harmonic stability, particularly …
-
Preliminary design tools in turbomachinery: Non-uniformly spaced blade rows, multistage interaction, unsteady radial waves, and propeller horizontal-axis turbine optimization
… for quantifying the impeller wake convection and pressure wave propagating between a centrifugal compressor impeller and diffuser vane; and 4) a semi-analytical model based Lifting line theory for unified propeller and horizontal-axis turbine optimization. Each model has been thoroughly validated …
-
POLYMER–BASED RESONANT WAVEGUIDE GRATING STRUCTURE AND ITS APPLICATIONS
… is demonstrated to work effectively as a pressure sensor. The external applied pressure is measured optically by the spectrum resonance peak shift the developed sensor incurs. The sensitivity of the demonstrated sensor can be tuned to different pressure ranges by adjusting the layer …
-
Acoustical and flow characteristics of a cough as an index of pulmonary function in the guinea pig
… were derived from the analysis of the sound pressure waves recorded during the cough. A principal component analysis was performed on the acquired data, and the resulting parameters were used to train a single neuron feed-forward back propagation neural network. The classification system was …
-
Nascar Restrictor Plate Exhaust Manifold Design Strategies
… developed by Ricardo to analyze the dynamics of pressure waves, mass flows and energy losses in ducts, plenums and the intake and exhaust manifolds of various systems and machines. [1] The model was validated against experimental data from a current NASCAR Winston Cup restrictor plate motor. The …
-
Numerical Simulation of Pressure Wave Supercharger with Pockets Operating at Different Speeds
Pressure wave supercharger is an application of wave rotor technology that utilizes compression waves produced by high-pressure engine exhaust gas to compress the fresh intake air within the channels. The phenomena within the wave rotor channels are governed by compression and expansion waves …
-
Acute arterial responses to physiological and psychological stress
… disease increases with higher levels of blood pressure, the early detection of those with hypertension becomes an increasing priority. Blood pressure is influenced by numerous factors, including the properties of the large arteries. This thesis sought to examine the effects of acute …
-
Characterization of the flow field response to vaneless space reduction in centrifugal compressors
… of loading on the impeller blade originates from pressure waves propagating with a phase difference on the suction and pressure surfaces of the blades. The frequency of the waves is set by the diffuser vanes passing frequency and the wavelength by the product of the diffuser vane passing period …
-
The development and analysis of a mobile explosive containment unit for on-board aircraft protection
… the detonation pulse, ensuing shock and pressure waves. This methodology was developed with the purpose of mitigating these explosive effects. The information concerning the material properties, shape and sizes of an explosive containment unit were all analyzed to identify one optimal …
-
Crackle noise from high-speed free-shear-flow turbulence
… and intermittent character. The corresponding pressure fluctuations also have a peculiar shape with strong, steep compressions and weaker, rounded expansions, which is thought to be responsible, at least in some part, for their distinct perception. A complete explanation of this distinct and …
-
An approximate method for the transient response of nonlinear systems
… such as earthquake tremors, wind gust forces and pressure, and pressure waves from explosions. Of the various assumptions which the engineer must make when studying the dynamic response of structures, one of the most important is perhaps the model representation of the true structure. One method …
-
Micro Electrostatic Actuation of a Silicon Diaphragm
… adequate diaphragm deflection to create audible pressure waves with relatively low maximum stresses to ensure a high cycle fatigue life. With these requirements, initial calculations and FEA (finite element analysis) were performed to establish the optimal square diaphragm side length combined …
-
Effect of Age on the Structure of Meissner Corpuscles in Forepad Digital Pads of Mice
… effect on the physical transmission of pressure waves to the transducer. The significance of mitochondrial degeneration and lipofuscin accumulation was considered. Atrophic corpuscles seen in abundance by old age probably occurred as a consequence of age-changes in axonal transport …
-
Experimental and numerical investigation of wire waveguides for therapeutic ultrasound angioplasty
… through a combination of direct ablation, pressure waves, cavitation and acoustic streaming caused by distal-tip displacements at ultrasonic frequencies. Numerical and experimental methods are used to investigate the outputs of the wire waveguides during ultrasonic activation. A …
-
Vibration damping using low-wave-speed media with applications to precision machines
… the powder can be modeled as a fluid in which pressure waves can propagate and find that such a model matches the experiments well. These findings suggest that any moderately lossy medium in which the speed of wave propagation is sufficiently low can be used to obtain similar responses.
-
Transient Analysis in Pipe Networks
… systems are all capable of generating high pressure waves in domestic water supply systems. These transient conditions resulting in high pressures can cause pipe failures by damaging valves and fittings. In this study, basic equations for solving transient analysis problems are derived using …
-
The role of the free fatty acid, lauric acid, in appetite regulation and its potential as an appetite-suppressant.
… markedly suppresses energy intake, modulates pressure waves in the antropyloroduodenal (APD) region and stimulates glucagon-like peptide-1 (GLP-1) secretion, while both C12 and C10 stimulate cholecystokinin (CCK) secretion, however, the effect of C12 was much greater. A previous study in …
Page 1 of 3