Thesis (Ph.D.)--University of Ottawa, 2008. / Includes bibliographies.

Thesis (M.S.)--University of Wisconsin--Madison, 1970. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

No description available.

Dust and gas in protoplanetary disks are the building blocks of planets. In this thesis, we study the dynamics of the gas and dust, which are crucial for the planet formation theory, using observational and numerical approaches. The observational part contains the case study of a rare circumtriple disk around the GW Ori hierarchical triple system. We present Atacama Large Millimeter/submillimeter Array (ALMA) observations of 1.3 mm dust continuum and 12CO J = 2-1 molecular gas emission of the disk. For the first time, we identify three dust rings in the GW Ori disk at ~46, 188, and 338 au, with the outermost ring being the largest dust ring ever found in protoplanetary disks. We use visibility modeling of the dust continuum and kinematics modeling of CO lines to show that the disk has misaligned parts, and the innermost dust ring is eccentric. We interpret these substructures as evidence of ongoing dynamical interactions between the triple stars and the circumtriple disk. In the numerical part, we study whether or not dust around gas gaps opened by planets can remain settled by performing three-dimensional, dust-plus-gas simulations of protoplanetary disks with an embedded planet. We find planets that open gas gaps 'puff up' small, sub-mm-sized grains at the gap edges, where the dust scale-height can reach 80% of the gas scale-height. We attribute this dust 'puff-up' to the planet-induced meridional gas flows previously identified by Fung and Chiang. We thus emphasize the importance of explicit 3D simulations to obtain the vertical distribution of sub-mm-sized grains around planet gaps. We caution that the gas-gap-opening planet interpretation of well-defined dust rings is only self-consistent with large grains exceeding mm in size. / Graduate

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Meteorology, 1980. / Microfiche copy available in Archives and Science. / Vita. / Includes bibliographical references. / by William Allan Perrie. / Ph.D.

京都大学 / 新制・課程博士 / 博士(工学) / 甲第24611号 / 工博第5117号 / 新制||工||1978(附属図書館) / 京都大学大学院工学研究科航空宇宙工学専攻 / (主査)教授 大和田 拓, 教授 髙田 滋, 講師 杉元 宏 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

No description available.

A weak shock theory is developed which allows for dense gas effects when the fundamental derivative of gas dynarnics, Γ , becomes small and possibly negative. The nonclassical behavior in these negative Γ regions has potential applications in turbomachinery design. The weak shock development results in a Burgers equation which is then solved numerically using the well-known MacCormack scheme. The results include the demonstration of many non-classical results such as expansion shocks, compression fans, shock-splitting and shock-fan combinations. Results are shown which could help improve turbine efficiency. / M.S.

Transonic flow of dense gases for two-dimensional, steady state, flow over a NACA 0012 airfoil was predicted analytically. The computer code used to model the dense gas behavior was a modified version of Jameson's FLOS2 airfoil code. The modifications to the code enabled modeling the dense gas behavior near the saturated vapor curve and critical pressure region where the fundamental derivative, Γ, is negative. This negative Γ region is of interest because the nonclassical gas behavior such as formation and propagation of expansion shocks, and the disintegration of inadmissible compression shocks. The results of this study indicated that dense gases with undisturbed thermodynamic states in the negative Γ region show a significant reduction in the extent of the transonic regime as compared to that predicted by the perfect gas theory. The results of the thesis support existing theories and predictions of the nonclassical, dense gas behavior from previous investigations. / Master of Science

Tests were performed to study the mechanism of shock formation in supersonic flow in long orifices to gain insight into the leakage flow of turbine tip gaps. The flow was modeled on a water table using a sharp-edged rectangular channel. The hydraulic analogy between free surface water flows and compressible gas flows was used to study the implications of the water table flow on tip leakage flows. The flow on the water table exhibited oblique hydraulic jumps starting on the channel sidewall near the channel entrance. This flow was analyzed using the oblique hydraulic jump relations developed by classical hydraulic theory. The results of this analysis suggested a model for the formation of the jump. As the flow accelerates around the corner of the channel entrance, supercritical free stream flow is turned as it intersects the sidewall. The abrupt change in flow direction results in the formation of the oblique hydraulic jump. An acceptable hydraulic analogy of compressible gas flows with shocks was obtained by reducing the surface tension of the water and using a large model size. The modified analogy for non-isentropic flow then allowed quantitative evaluation of the modeled shock structure in a compressible flow field. The predicted shock formation in such a flow has possible implications for both the efficiency of a gas turbine and the useful life of the turbine blade. / Master of Science