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Two-dimensional numerical simulation of bubble dynamics in microgravity is performed employing a Volume of Fluid (VOF) solver. Shape oscillation and deformation of bubbles under forced vibration are studied. Coupling between the oscillatory translational motion and shape deformation results in nonlinear behavior of bubbles at high amplitudes and frequencies. As a result of oscillation of the buoyancy force, the pressure field around the bubbles oscillates and bubbles interact with each other. Effect of vibration frequency and amplitude and liquid to gas density ratio on the shape of bubbles and bubble-bubble interaction is studied. It is shown that the shape of the bubbles in response to the forced vibrations mainly depends on the acceleration of the vibration.

Dynamics of endolymph and cupula in a semicircular canal subject to high frequency oscillations imposed on the endolymph at the open section of the canal is investigated. Deformation of cupula inside the endolymph fluid is simulated numerically. A high frequency and high amplitude periodic oscillations may result in the formation of vortical motions inside the semicircular canals. The number of vortices increases with the oscillation frequency. As a result of asymmetry of the canal geometry, there is an asymmetry in the pressure variation across the cupula resulting in a net motion of cupula in a specific direction during each cycle. The motion of the cupula depends on the vibration amplitude and frequency.

The Canadian Supercritical Water-Cooled Reactor (SCWR) is a 1200 MW(e) channel-type nuclear reactor. The reactor core includes 336 vertical pressurized fuel channels immersed in a low-pressure heavy water moderator and calandria vessel containment. The supercritical water (SCW) coolant flows into the fuel channels through a common inlet plenum and exits through a common outlet header. One of the main features of the Canadian SCWR concept is the high-pressure (25 MPa) and high-temperature (350°C at the inlet, 625°C at the outlet) operating conditions that result in an estimated thermal efficiency of 48%. This is significantly higher than the thermal efficiency of the present light water reactors, which is about 33%. This paper presents a description of the Canadian SCWR core design concept; various numerical analyses performed to understand the temperature, flow, and stress distributions of various core components; and how the analyses results provided input for improved concept development.