Internal Flow Applications Research Articles

EXPERIMENTAL INVESTIGATION INTO FACTORS AFFECTING THE TRANSIENT FLOW OF FLUID THROUGH AN ORIFICE IN REALISTIC CONDITIONS

During operations, damage can occur with a resulting ingress or egress of fluid. The incoming water affects the reserve buoyancy and it can also change stability and hull girder loading. During a flooding event it is vital that the flow through the damaged orifice and the movement of floodwater around the structure can be predicted quickly to avoid further damage and ensure environmental safety. The empirical measure coefficient of discharge is used as a simplified method to quantify the flooding rate. In many internal flow applications the coefficient of discharge is estimated to be 0.6 but recent research shows that it can vary considerably when applied to transient flooding flows. This paper uses an experimental setup to investigate how changes to the orifice edges and position within the structure affect the flow. It is then used to investigate the coefficient in a more realistic scenario, a static compartment in waves.

On the interaction of an oblique shock with a flexible panel

In this communication, the dynamics of a flexible two-dimensional panel subjected to an impinging oblique shock is considered numerically in the inviscid regime. Computations have been performed for a Mach number equal to two and for several shock strengths employing a previously validated fluid–structural approach. Results show for the first time that for a sufficiently strong shock self-excited oscillations arise in the coupled system. Depending on the shock strength, either supercritical or subcritical bifurcations emerge at a value of dynamic pressure which can be considerably lower than that corresponding to standard panel flutter (i.e., in the absence of a shock). For fixed dynamic pressure, both the amplitude and frequency of the limit-cycle oscillations increase with the impinging shock strength. In addition to the incident and reflected oblique shocks, the unsteady flows are characterized by a shock at the plate leading edge and by a strong recompression and subsequent expansion near the trailing edge. The significant unsteadiness generated by the fluttering panel propagates along the reflected shock and trailing-edge recompression/expansion wave system with potential structural implications not only on the panel but on opposing surfaces in internal flow applications.

Chemical engineering fluid mechanics

Basic concepts dimensional analysis and scale-up fluid properties in perspective fluid statics conservation principles pipe flow internal flow applications pumps and compressors compressible flows flow measurement and control externalflows fluid-solid separations by free settling flow in porous media fluidization and sedimentation two-phase flow appendices.

Efficiency Improvement of Unified Implicit Relaxation/Time Integration Algorithms

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Global pressure relaxation for laminar two-dimensional internal flow

This study extends the reduced Navier-Stokes (RNS) global pressure relaxation procedure developed by Rubin and co-workers for external flow to internal flow applications. The streamwise pressure gradient is split into a backward-differenced or initial value component, as in boundary layer marching, and a forward-differenced or boundary value component that represents the elliptic downstream effects. The streamwise convection terms are upwind-differenced and all other streamwise derivatives are backward-differenced. A standard boundary layer marching technique imbedded in a conventional line relaxation technique is obtained. For compressible flow the pressure iteration determines the interior flow interaction as well as the inlet mass flux that is consistent with the outflow pressure boundary condition. Results have been computed for incompressible flow in both rectangular and curved channels, and for subsonic compressible flow in the simulation of an aerofoil in a wind tunnel. Converged solutions were obtained over a range of Reynolds numbers generating small to moderately large separation bubbles.