This thesis presents the numerical solution for two-dimensional incompressible viscous flow over a rigid bluff body which is elastically supported or alternately undergoing a specified harmonic oscillations. Solutions for the related associate flow in which the body is at rest in a two-dimensional incompressible time-dependent viscous flow have also been -obtained. This work is an extension of the work by Pattani [19] to include the effect of a steady far field flow on an oscillating body. The numerical model utilizes the finite element method based on a velocity-pressure primitive variable representation of the complete Navier-Stokes equations. Curved isoparametric elements with quadratic interpolation for velocities and bilinear interpolation for pressure are used. Nonlinear boundary conditions on the moving body are represented to the first order in the body amplitude parameter. The method of averaging is used to obtain the resulting periodic motion of the fluid. Three non-dimensional parameters are used to completely characterise the flow problem: the frequency Reynolds number Rω , the Reynolds number of steady flow Rℯ₁ and the Reynolds number for time-dependent flow Rℯ₂. Numerical results are obtained for a circular body, a square body and an equilateral triangular body. A parametric study is conducted for different values of the Reynolds numbers in the viscous flow regime. In all cases, results are obtained for streamlines, streaklines, added mass, added damping, added force and the drag coefficients. The limiting cases of steady flow over a fixed body and an oscillating body in a stationary fluid are checked with known results. Results for the associated flow are also obtained. The transformations derived, between the two associated flows are checked. Good agreement is obtained between the present results and other known results. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

Background: Non-obstructive Dysphagia (NOD) is one of the most common symptoms evaluated using esophageal manometry. Although manometry is considered the gold standard, many NOD patients have normal evaluations. Esophageal function testing with combined multichannel intraluminal impedance and esophageal manometry (MII-EM) is performed using ten 5-mL swallows of a liquid and a viscous material and provides supplemental information about bolus transit. The aim of this study was to evaluate esophageal function using combined MII-EM in patients with NOD who had normal evaluations with liquid manometry. Methods: Multichannel intraluminal impedance and esophageal manometry was performed in consecutive patients presenting for evaluation of NOD. Patients were excluded if any abnormality was detected during liquid manometry. Viscous manometry and liquid and viscous impedance data were analyzed to detect manometric or bolus transit abnormalities. Patients referred for GERD evaluation without any swallowing complaints were used as patient controls and were subject to the same exclusion criteria as the NOD group. All swallow evaluations were performed with 10 liquid and 10 viscous swallows. Key Results: Data from 240 patients were evaluated, 129 with NOD and 111 patient controls. In the NOD group, 9% (12/129) had abnormal liquid impedance and 29% (37/129) had abnormal viscous impedance. In the control group, 4% (4/111) had abnormal liquid impedance and 16% (18/111) had abnormal viscous impedance. Chi-square analysis showed a significant difference between the two study groups for viscous impedance (P = 0.02) but not for liquid impedance (P = 0.12). Conclusions and Inferences: Our data support our belief that a normal liquid manometry with an abnormal viscous impedance analysis in a patient with NOD indicates abnormal esophageal motility. Therefore, viscous impedance should be performed on all patients during the evaluation of NOD.

Background: Non-obstructive Dysphagia (NOD) is one of the most common symptoms evaluated using esophageal manometry. Although manometry is considered the gold standard, many NOD patients have normal evaluations. Esophageal function testing with combined multichannel intraluminal impedance and esophageal manometry (MII-EM) is performed using ten 5-mL swallows of a liquid and a viscous material and provides supplemental information about bolus transit. The aim of this study was to evaluate esophageal function using combined MII-EM in patients with NOD who had normal evaluations with liquid manometry. Methods: Multichannel intraluminal impedance and esophageal manometry was performed in consecutive patients presenting for evaluation of NOD. Patients were excluded if any abnormality was detected during liquid manometry. Viscous manometry and liquid and viscous impedance data were analyzed to detect manometric or bolus transit abnormalities. Patients referred for GERD evaluation without any swallowing complaints were used as patient controls and were subject to the same exclusion criteria as the NOD group. All swallow evaluations were performed with 10 liquid and 10 viscous swallows. Key Results: Data from 240 patients were evaluated, 129 with NOD and 111 patient controls. In the NOD group, 9% (12/129) had abnormal liquid impedance and 29% (37/129) had abnormal viscous impedance. In the control group, 4% (4/111) had abnormal liquid impedance and 16% (18/111) had abnormal viscous impedance. Chi-square analysis showed a significant difference between the two study groups for viscous impedance (P = 0.02) but not for liquid impedance (P = 0.12). Conclusions and Inferences: Our data support our belief that a normal liquid manometry with an abnormal viscous impedance analysis in a patient with NOD indicates abnormal esophageal motility. Therefore, viscous impedance should be performed on all patients during the evaluation of NOD.

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Approved for public release; distribution is unlimited / Cebeci's viscous/inviscid interaction program was applied to the analysis of steady, two dimensional, incompressible flow past four airfoils, the NACA 66₃-018, 0010 (Modified), 4412 and the Wortmann FX 63-137. Detailed comparisons with the available experimental results show that the essential features are correctly modelled, but that significant discrepancies are found in regions of flow separations. / http://archive.org/details/computationalinv00math / Lieutenant, United States Navy

Ahuna Mons is a 4 km tall mountain on Ceres interpreted as a geologically young cryovolcanic dome. Other possible cryovolcanic features are more ambiguous, implying that cryovolcanism is only a recent phenomenon or that other cryovolcanic structures have been modified beyond easy identification. We test the hypothesis that Cerean cryovolcanic domes viscously relax, precluding ancient domes from recognition. We use numerical models to predict flow velocities of Ahuna Mons to be 10-500 m/Myr, depending upon assumptions about ice content, rheology, grain size, and thermal parameters. Slower flow rates in this range are sufficiently fast to induce extensive relaxation of cryovolcanic structures over 10(8)-10(9) years, but gradual enough for Ahuna Mons to remain identifiable today. Positive topographic features, including a tholus underlying Ahuna Mons, may represent relaxed cryovolcanic structures. A composition for Ahuna Mons of >40% ice explains the observed distribution of cryovolcanic structures because viscous relaxation renders old cryovolcanoes unrecognizable.