Open-water rudder tests using CFD
Van Hoydonck, W.; Delefortrie, G.; De Maerschalck, B.; Vantorre, M. (2019). Open-water rudder tests using CFD, in: 32nd Symposium on Naval Hydrodynamics, Hamburg, Germany, 5-10 August 2018: proceedings. pp. [1-14] In: (2019). 32nd Symposium on Naval Hydrodynamics, Hamburg, Germany, 5-10 August 2018: proceedings. not yet published. [S.n.]: [s.l.]. , more |
| Available in | Authors | | Document type: Conference paper
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| Authors | | Top | - Van Hoydonck, W., more
- Delefortrie, G., more
- De Maerschalck, B., more
- Vantorre, M., more
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| Abstract | In this paper, results are presented of research to use Computational Fluid Dynamics (CFD) methods to determine open-water rudder characteristics at Flanders Hydraulics Research (FHR). Up till now, this data is obtained using towing tank tests, but the Reynolds number of the tank tests is at least three orders lower than in reality. The flow physics are very different at model scale (laminar flow with transition to turbulent flow) than at full scale (turbulent flow), which may have a significant impact on the resulting lift, drag and moment coefficients.
In the first part of the paper, CFD computations are executed for a limited grid convergence and validation study, where results are compared with experimental data obtained by Whicker and Fehlner (1958). Focus of the second part of the paper is on executing a number of unsteady CFD computations at full scale conditions to determine the lift, drag and moment coefficients on a symmetrical semi-balanced horn rudder for the full range of angles of attack (from 0 to 180 degrees). For the same geometry (isolated rudder blade), values for the lift in the ahead flow condition are similar to the experimental results. Once the geometry is modified by adding the horn and/or a mirror plane, differences are present for the whole range of angles of attack. It is shown that for the CFD computations tested at full scale, reliable coefficient graphs are obtained: the maximum lift coefficient in the astern flow condition is significantly lower than in the ahead condition and the lift curve slope in the ahead condition is steeper than in the astern condition. The modelled full scale drag values are also significantly lower than those obtained in the towing tank experiments. |
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