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Cavitation is a significant problem for the shipping industry as it can lead to ship vibration and erosion, both resulting in increased maintenance costs. Therefore, a better understanding of cavitation and an accurate prediction capability are important. Lloyd's Register has performed cavitation observations and measurements at ship scale and, from that, has developed a better understanding of cavitation and its effects, which are discussed in this paper. These observations showed that details of the cavitating flow are paramount for the erosive potential of the flow. Furthermore,...
Numerical investigations of turbulent natural convection between concentric, cylinders has been carried out. Large Eddy Simulations (LES) have been performed on three different geometries. The first two consider a single inner cylinder at gap-based Rayleigh numbers of 1.18×109 and 2.38×1010 and an aspect ratios Ro/Ri=4.87 and 3.37, respectively. The last LES run considers three internal cylinders. It reveals that the flow patterns in the decay heat pen are more complex than the one internal concentric cylinder cases. The two-equations RANS models predictions for this test case are less...
This study is related to mixed convection heat transfer of air flowing through an ascending vertical annular passage with significant radiation heat transfer. This configuration leads to a maximum level of heat transfer impairment similar to the one obtained in pipe flows. Five turbulence model predictions are compared with the experimental data obtained by the Promethée facility. Both k–w models (Wilcox and SST) tend to overestimate heat transfer in mixed convection while the standard low-Re number k-e underestimates it. The AKN low-Re model performs poorly in all cases. Finally, only the v²...
The paper surveys developments in CFD applications for maritime structures (ships, propellers and offshore structures) over the past decade. Progress is significant in integrating the process chain,particularly more automated model generation. Increased hardware power and progress in various aspects of the flow solvers allow more sophisticated applications and wider scope of applications.Selected examples taken from industry and research applications show the increasing importance of CFD in earlier design stages.
Probability density function (PDF) methods provide an elegant and effective resolution to the closure problems that arise from averaging or filtering chemical source terms and other nonlinear terms in the equations that govern chemically reacting turbulent flows. PDF methods traditionally have been associated with studies of turbulence-chemistry interactions in laboratory-scale, atmospheric pressure, nonluminous, statistically-stationary nonpremixed turbulent flames; and Lagrangian particle-based Monte Carlo numerical algorithms have become the predominant method for solving modeled PDF...
In recognition of continuing difficulties that are experienced in performing computational analyses (CAE) on real turbine blades, this paper explores current developments in areas of integrated geometry handling, multi-domain meshing and multi-disciplinary analysis. The application of an integrated software framework first for CAD repair, then for surface and volume meshing, and finally for combined fluid, thermal and stress analysis can go some way to easing pains. The focus here is to demonstrate how it is possible in a single simulation environment, and using a finite volume methodology,...
This paper presents a comprehensive study on the CFD simulation of a radial fan with forward curved blades emphasizing on turbulence models and unstructured grids. Three of the most widely used turbulence models i.e. Realizable k-ε, SST k-ω and Spalart-Allmaras are validated with the available experimental results. The model performance comparison is based on the characteristic curves and the velocity fields obtained from each model. The other part of the study concentrates on the unstructured grids, addressing the influence of cell shapes on the accuracy of the results. The verification...

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