Abstract
One of the important challenges in the design and construction of planing craft is the occurrence of longitudinal instability at high speeds. Among the methods that can be used to reduce or eliminate these instabilities is the use of hydrofoil stabilizer. In this research, the influence of the dimensions of the hydrofoil stabilizer on the dynamic behavior of the mono-hull planing craft has been investigated. The vessel studied in this research is a planing mono-hull craft, which experimentally has longitudinal instability. The influence of the speed on the effect of porpoising on the planing craft is also studied. The purpose of this study was to analyze the performance of a high-speed planing craft with a hydrofoil stabilizer and determine the best dimensions of the hydrofoil stabilizer. In this research, the parameters of hydrofoil dimensional ratios and middle width ratio in stingray type hydrofoils have been investigated. Each of these parameters is modeled in its position with the help of a CAD software. A computational fluid dynamics solver has been used for the numerical simulation of the problem. In this article, an attempt has been made to understand the importance of each of the design parameters by comparing the results of the simulation and examining the results related to pitch and heave motions of the planing craft. At this stage, in order to check the parameters, the angle of attack is 0 degrees, the depth of the hydrofoil to the transom of the boat is 15 cm, and the longitudinal distance of the hydrofoil from the transom is assumed to be 10 cm. One of the investigated parameters is the width to the chord length ratio of the hydrofoil, which has a fixed cross section. From the comparison of the results between the three ratios of 0.75, 1.33 and 2.083, it was found that at a speed of 30 knots and in a time of 3 seconds, the range of pitch movement has been reduced by 50, 36.6 and 63.3%, respectively, compared to the case without hydrofoil. Therefore, i