The sound generated by a vortex propagating across a two-dimensional duct section with flexible walls (membranes) in an infinitely long rigid duct conveying a flow is investigated numerically using the matched asymptotic expansion technique and the potential theory. The effects of the initial vortex position, the mechanical properties of the flexible walls, and the mean flow on the sound genera...

Weakly convex polyhedra which are star-shaped with respect to one of their vertices are infinitesimally rigid. This is a partial answer to the question whether every decomposable weakly convex polyhedron is infinitesimally rigid. The proof uses a recent result of Izmestiev on the geometry of convex caps.

Department of Chemistry Doctor of Philosophy by Gary Mark Doctors Patient-specific Computational fluid dynamics (CFD) studies of cerebral blood flow have the potential to help plan neurosurgery, but developing realistic simulation methods that deliver results quickly enough presents a major challenge. The majority of CFD studies assume that the arterial walls are rigid. Since the lattice-Boltzm...

Based on a series of shaking table model tests, it was found that the eŠects of 1) subsoil and backˆll deformation, 2) failure plane formation in backˆll, and 3) pullout resistance mobilized by the reinforcements on the seismic behaviors of the geosynthetic reinforced soil retaining walls (GRS walls) were signiˆcant. These eŠects cannot be taken into account in the conventional pseudo-static ba...

The mechanisms by which Cordilleran plutons are emplaced vary widely. However, the present authors have examined a series of plutons ranging from 2–35 km emplacement depth that have many common features, which suggest that downward transport of host rock is the most important mechanism during magma ascent and pluton emplacement. Many of these Cordilleran plutons preserve gently dipping, unfault...

A theoretical model is developed to investigate the effect of compliant coatings on radiated sound from low Mach-number turbulent boundary layers over otherwise rigid surfaces. Lighthill’s analogy is employed and the primary noise source is assumed to be from wall-pressure fluctuations. Parametric studies are performed on the behavior of the material properties such as the speed of sound and de...

The Unreinforced Wall (URM) elements that are most susceptible to out-of-plane failure are wall elements of the upper storeys where the accelerations are largest. In modern URM buildings with reinforced concrete slabs, the out-of-plane mechanism involves typically a storey-high wall element, which is subjected at its base and top to the accelerations of the corresponding floor slabs. The accele...

Linear stability analysis is performed for the onset of thermosolutal convection in a horizontal fluid layer with rigid-rigid boundaries. The temperature field between the walls of the fluid layer consists of two parts: a steady part and a time-dependent periodic part that oscillates with time. Only infinitesimal disturbances are considered. The effect of temperature modulation on the onset of ...

This paper addresses the often-cited problems associated with haptic display of rigid bodies or “virtual walls”. Traditional haptic interfaces employ an actuator directly coupled to the human operator that provides a force proportional to wall penetration distance and velocity. A new paradigm for design and control of haptic displays is proposed that utilizes a de-coupled actuator and pre-conta...

The elastic response is studied of (i) a single flexible chain grafted on a rigid plane and (ii) an ensemble of non-interacting tethered chains. It is demonstrated that the entropic theory of rubber elasticity leads to conclusions that disagree with experimental data. A modification of the conventional approach is proposed, where the end-to-end distribution function (treated as the governing pa...