Marine Hydrodynamics

Established in 1935, the largest and oldest lab of its kind, the Davidson Laboratory was the first facility in the nation to test sailing yacht designs in a towing tank. It earned an international reputation for its work in physical and computer modeling of marine craft designs ranging from high-speed planning boats to America Cup yachts.

Model testing is done to determine the behavior of vessels at full scale without the expense of actually building the real vessel until the design is proven on a small scale. Model building is several thousand years old, as models are known to have been used and tested in Egypt. Today, computer simulation supplements physical models, but computer models are insufficiently reliable and a priori correct to be used without careful calibration against reality. Thus even when computer models are used, usually a physical model is built, and the computer model is carefully calibrated from the physical one.

The Davidson Laboratory has experience in a variety of areas including:

  • Examination of the stability, control and behavior of all types of marine craft in environments ranging from calm water to random sea states.
  • Physical model testing and computer simulation of advanced marine craft such as submarines, seaplanes, amphibious vehicles and planning craft.
  • Fundamental research in marine hydrodynamics, including the analysis of flow around submerged vehicles, propeller-turbulence interaction and wave dynamics.

Numerical Hydrodynamics

CFD has become increasingly important for ship resistance and powering, especially in the early stage where new designs of hullforms and appendages can be explored rapidly to come up with a promising design. The final ship design is still tested in a towing tank to validate the intended performance and to get accurate prediction of powering and seakeeping performance. Thus the numerical towing tank is an excellent supporting tool for our experimental towing tank.

The laboratory has educational license to a CFD program called SHIPFLOW developed by Flowtech. It is a special purpose software for investigating the hydrodynamics of ships and other marine vehicles and more details can be found at www.flowtech.se

Savitsky Method

The laboratory has also developed codes for the hydrodynamic evaluation of high-speed planing hulls based on Savitsky's semi-empirical theory.