Hydrodynamic Effects of Heave plates

Student thesis: Master Thesis and HD Thesis

  • Hans Lindenchrone Dueholm
  • Lars Kristensen
4. term, Structural and Civil Engineering, Master (Master Programme)
A downsized model of a circular heave plate attached to the bottom of a cylinder is modelled for a variety of oscillatory motions and disc radii, by means of theoretical calculations, Smoothed Particle Hydrodynamcis (SPH) simulations, and physical experiments. The resultant time series of the three models are analysed and the force amplitudes, added mass and drag coefficient are found and used as points of comparison.

From the comparison it is evident that both the theoretical and SPH models do not simulate the hydrodynamics of the heave plate very well. The theoretical calculations does not yield results with consistent margins of error as the parameters of the model is changed. The SPH simulations has large margins of error for the tested cases with lower velocities and smaller heave plates, and in turn smaller margins of error for cases with higher velocities and larger heave plates.

Plausible reasons for the errors of the two models where discussed and looked into. No concrete reasoning for the error of the theoretical calculations were found. The correlation of the margin of error, heave plate radius and velocity for the SPH simulations were presumed to be caused by the choice of viscosity scheme used in the simulations, although no clear solution to this problem is found.

Lastly it is concluded that the theoretical model should only be used for very rough estimations, and SPH simulations can be used to find hydrodynamic constants given that the velocity related errors are solved.
Publication date10 Jun 2021
Number of pages126
ID: 414381123