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 113 for “"rough surfaces"”.
-
Turbulent Flow Over Rough Surfaces
… flow structure in repeated-rib geometry rough-walled surfaces in two size pipe systems as a function of the ratio of roughness height to spacing distance between the elements (P/K), the axial variation of the flow, and the flow rates. The variations in P/K geometries caused the flow …
-
Ionic liquid behavior on rough surfaces
Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2018-05-01
-
Elastohydrodynamic lubrication of smooth and rough surfaces
… Lubrication (EHL) are studied. For smooth surfaces, a novel approach which solves separately the inlet and outlet regions by using the fracture mechanics equations, is proposed to solve EHL line contacts for shape and pressure. For rough surfaces, the full EHL geometry is reduced to an …
-
High-frequency electromagnetic wave scattering from rough surfaces
"A new technique in solving the rough surface scattering problem is presented. The method employed, entitled the ""shooting and bouncing rays"" (SBR) method, is based on a combination of the geometric optics (GO) theory and the physical optics (PO) theory. The SBR method improves on the Kirchhoff …
-
Contact between models of rough surfaces containing spherical asperities
… for determining the true area of contact between surfaces as well as a number of theories for predicting contact areas in the case of elastic, plastic, and elasto-plastic deformation of contacting surface asperities are reviewed. The effect of tangential loading upon the area of contact is also …
-
Electromagnetic backscattering from penetrable rough surfaces based on moment method
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.
-
Wall Jet Boundary Layer Flows Over Smooth and Rough Surfaces
… wall jet flow into still air over smooth and rough surfaces has been investigated in a recently constructed wall jet wind tunnel testing facility. The facility has been shown to produce a wall jet flow with Reynolds numbers based on the momentum thickness, Re<SUB>&delta</SUB> = …
-
Open channel turbulent boundary layers and wall jets on rough surfaces
… many flows of practical interest occur on rough surfaces, our understanding and ability to predict rough wall turbulent flows lags far behind the corresponding technology for smooth surfaces. This provides reasonable grounds for additional refined rough wall measurements with the …
-
The importance of scale structure in scattering from random, rough surfaces
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1998.
-
A Study of Electromagnetic Scattering of Communication Signals by Randomly Rough Surfaces
… to communication signal propagation studies through the use of Fourier decomposition thereby allowing the analysis and prediction of communication signals propagating over rough surfaces. Current methods of predicting and analyzing communication signal propagation rely on either using only a …
-
A new method to calculate wave scattering from rough surfaces at low grazing angles
… perfect electric conducting arbitrarily rough surfaces which are planar in the mean. The technique allows for the calculation of the scattered fields in the low grazing angle regime, i.e., when the incident wave propagation vector approaches the horizontal to the mean surface plane, or in …
-
A Study of Sound Generated by a Turbulent Wall Jet Flow Over Rough Surfaces
… field acoustics generated by turbulent flow over rough surfaces has been experimentally investigated in an acoustically treated wall jet facility. The facility allows direct measurement of the far field sound from small patches of surface roughness, without contamination from edge or other …
-
GENERATION, MECHANICAL AND STATISTICAL ANALYSIS, AND FEM SIMULATION OF FRACTURE OF REPEATABLE RANDOM ROUGH SURFACES
… in service nearly always generate surface roughness, and follow the Central Limit Theorem prediction for surface topology. This study couples experimental and statistical theory, and FEM to extend knowledge of life of materials from initial service surface conditions through surface damage …
-
Measurements and modelling of reflection and transmission from smooth and rough surfaces at 62 GHz
… of the scattered field from rough surfaces have also been presented. Purpose made rough surfaces have been constructed by impregnating concrete slabs by 10, 20 and 40 mm angular stones. Two building facades one made from big stone and the other being pebble-dash have also been …
-
Turbulent fluid flow and heat transfer in annular passages with rough surfaces and moving cores.
… developed fluid flows in concentric annuli with rough surfaces and moving cores, by analytically predicting the effects of surface roughness, core velocity and turbulent motion on the momentum and heat transfer characteristics of the flow, such as friction forces, velocity profiles, temperature …
-
Turbulent Boundary Layers over Rough Surfaces: Large Structure Velocity Scaling and Driver Implications for Acoustic Metamaterials
… turbulent boundary layers over rough surfaces, for 30,000≤〖Re〗_θ≤100,000. Relationships between fluctuating pressures and velocities were explored through the pressure Poisson equation. Certain scaling laws were implemented in attempts to collapse velocity spectra and turbulence …
-
Pressure Fluctuations in a High-Reynolds-Number Turbulent Boundary Layer over Rough Surfaces of Different Configurations
… fluctuations under a high Reynolds Number, rough-wall, turbulent, boundary layer have been studied in the Virginia Tech Stability Wind Tunnel. Rough surfaces of varying element height (1-mm, 3-mm), shape (hemispheres, cylinders) and spacing (5.5-mm, 10.4-mm, 16.5-mm) were investigated in …
-
Influence of surface roughness and sliding speed on the friction and wear of low density polyethylene
The effect of surface roughness and sliding speed on the wear mode of low density polyethylene was studied with multipass experiments at the high sliding speeds by the use of a pin-on-disk wear machine. Surface roughness was found to be the major parameter in determining the wear mode of the …
-
MULTI-SCALE DYNAMICS OF MECHANICAL SYSTEMS WITH FRICTION
Contact between rough surfaces occurs in numerous engineering systems and in many instances influences the macro behavior of the system. In many instances, the interaction between rough surfaces, affect the macro behavior of the system. Effective treatment of systems containing rough surface …
Page 1 of 6