A Measurement System for the Environmental Load Assessment of a Scale Ship Model—Part II

Abstract

In the process of ship motion control system design, it is necessary to take into account the impact of environmental disturbances such as winds, waves and sea currents. The commonly used representatives of wave influences in this area are the unidirectional wave power spectral density functions describing sea waves of different form: long-crested, fully developed waves, developing wind waves or multi-modal waves (e.g., with swell). The existing standard PSD models describe the surge of open sea or ocean. However, they are inadequate in the case of control system testing of scale ship models for sailing in open water areas such as lakes or test pools. This paper presents a study of wind-generated wave PSD estimations for a small lake used as a test area for free-running scale ships. The publication provides a brief overview of the wave spectral density functions commonly used for control system design. A measurement instrument using the idea of a water-induced variable capacitance that works synchronously with the wind sensors is also described. The process of collected data analysis is presented. As a result of the study, a series of empirical spectral density functions of lake waves for different wind speeds are obtained. They correspond to the rescaled, two-parametric ITTC model.

Modeling of an Autonomous Electric Propulsion Barge for Future Inland Waterway Transport

“…The first difference is the hydrometeorological conditions. On the one hand, the barge is subject to a limited influence of environmental conditions such as waves [30], due to the waters being confined by the land, and wind, due to the small height of the ship itself. On the other hand, navigation on rivers and some canals usually involves being exposed to the influence of the river current and the associated asymmetry of the propulsion load, depending on the direction of movement during a usually two-way cruise.…”