Modelling of Lake Wind Parameters to Simulate Environmental Disturbances for a Scaled Ship Model

In the field of vessel motion control system design, it is of essential importance to consider the environmental disturbances which affect a ship’s hull, including wind, waves and currents. The conventional modelling techniques for wind disturbance simulation are designed to represent the behaviour of winds over open sea areas. However, before being implemented on a real seagoing vessel, its motion control systems are often tested on scale models built for a ship. Such tests are usually carried out on small bodies of water, where wind and wave models built for the open sea cannot be used. Therefore, a wind and wave model for a small body of water is required so that the effects of external disturbances on the motion of the scale model can be properly considered in the early stages of control system design. This paper presents the construction of a wind speed and direction simulator for a small lake, which was used as a test area for a free-floating, manned training vessel built at a 1:24 scale. This paper describes modifications made to the model, employing a von Karman spectrum to characterise the wind. These modifications were designed to align the model with the observed phenomena in a lake test area. The resulting model exhibits a clear structure and can be readily implemented both in software and on a microprocessor-based hardware platform.