This work addresses the experimental and numerical study of a stepped planing hull and the related fluid dynamics phenomena typically occurring in the stepped hull in the unwetted aft body area behind the step. In the last few years, the interest in high-speed planing crafts, with low weight-to-power ratios, has been increasing significantly, and, in such context, naval architects have been orienting toward the stepped hull solution. Stepped planing hulls ensure good dynamic stability and seakeeping qualities at high speeds. This is mainly due to the reduction of the wetted area, which is caused by the flow separation occurring at the step. This paper presents the experimental results of towing tank tests in calm water on a single-step hull model, which is the first model of a new systematic series. The same flow conditions are analyzed via Reynolds Averaged Navier-Stokes (RANS) and Large Eddy Simulations (LES), with different moving mesh techniques (overset/chimera and morphing grid), performed at different model speeds. The numerical results are in accordance with experimental data, and overset/chimera grid is found to be the best approach between the analyzed ones. The flow patterns obtained numerically through LES on a refined grid appear similar to the ones observed in towing tank investigations through photographic acquisitions. These flow patterns are dominated by a rather complex 3D arrangement of vortices originating from air spillage at both sides of the step. The understanding of these phenomena is important for the effectiveness of stepped hull designs.
Abstract
This work addresses the experimental and numerical study of a stepped planing hull and the related fluid dynamics phenomena typically occurring in the stepped hull in the unwetted aft body area behind the step. In the last few years, the interest in high-speed planing crafts, [...]
In this study, numerical simulations were conducted to investigate the changes in air circulation after the installation of fans in a large indoor sports hall. It was found that optimizing the arrangement of fans and the settings for doors and windows can significantly enhance air convection, improve the distribution of airflow, and increase the thermal comfort of athletes. The combination of natural ventilation systems with mechanical fans can further improve air quality and energy efficiency. These findings can provide practical recommendations for the design of sports halls, which are crucial for improving athletes’ performance and comfort, as well as enhancing the experience of spectators and other users. The analysis results indicate that in Model 2, the average wind speed of Scheme 7 is 1.6% higher than that of Scheme 5, 11.5% higher than that of Scheme 6, and 34.3% higher than that of Scheme 8. Therefore, Schemes 7 and 5 are identified as the optimal solutions for Model 2. When comparing the optimal solutions of both models, it was found that the average wind speed of Scheme 7 is 1.6% higher than that of Scheme 5, and 12% higher than that of Scheme 1, making Scheme 7 the overall optimal solution.OPEN ACCESS Received: 17/07/2024 Accepted: 31/10/2024 Published: 07/04/2025
Abstract
In this study, numerical simulations were conducted to investigate the changes in air circulation after the installation of fans in a large indoor sports hall. It was found that optimizing the arrangement of fans and the settings for doors and windows can significantly enhance [...]
Experimental and numerical hydrodynamic analysis of a stepped planing hull 