Computational Fluid Dynamics Investigation of the Spacing of the Aerodynamic Characteristics for Multiple Wingsails on Ships

Abstract

Wind energy, as an inexhaustible energy source, has become a focal point in the development of new energy for ships. Sail-assisted technology, which leverages wind power, has been successfully applied to ship propulsion. The propulsion performance of sail-assisted ships is affected by the interference characteristics among multiple wingsails. To investigate interference characteristics, an arrangement scheme involving two-element wingsails and considering the relative wind direction angle was established. To obtain the inter-stage interference characteristics of wingsails, the Reynolds average N-S equation was used in the numerical simulation conducted under steady operating conditions. The results indicate that, at the relative wind angles of 30°, 90°, and 120°, the minimum horizontal spacing in a single row arrangement scheme is 1.5c. However, at relative wind angles of 90° and 120°, inter-stage interference may induce stall conditions in the wingsails. In a double-row arrangement scheme, the wake of the upstream wingsail interferes with the flow of the downstream sail at relative wind angles of 90°. An optimal propulsion performance is achieved with a horizontal spacing of 4c and a longitudinal spacing of 10c. Moreover, the interference performance of the two-element wingsails can be enhanced through a horizontal offset arrangement. This study provides a reference for the arrangement of wingsails on ships.

Keywords

• sail-assisted ships
• wingsails
• interference characteristics
• numerical simulation