Seakeeping performance of a rounded hull catamaran in waves using CFD approach

Abstract

Prediction of the seakeeping performance of a ship in the earlier ship's design step is necessary to ensure the safety of navigation during sailing. To accommodate such a demand, this research proposes to analyse the seakeeping performance of a rounded hull catamaran. The vertical motion of the catamaran including the heave and pitch motions were quantified by her Response of Amplitude Operator (RAO). The Computational Fluid Dynamic software was used to develop the model, where several effects of various Froude numbers, hull lateral separation ratios and wavelengths on the heave, and pitch motions of the rounded hull catamaran have been taken into account. The results revealed that the higher Froude number associated with less hull lateral separation ratio was proportional to the subsequent increase of her heave and pitch motions. In the case of / ≤1.0, the seakeeping quality of the rounded hull catamaran has been improved and presented in the form of a sufficient reduction of the heave and pitch motions. It is shown that the estimated seakeeping performance of the rounded hull catamaran greatly depends on the Froude numbers and magnitude of wavelength.

Seakeeping Prediction of Deep-v High Speed Catamaran Using Computational Fluid Dynamics Approach

“…Although, the pitch motion decreases from 3.851286 ⁰ to 0.622232 ⁰. The result also showed that the higher the Froude number, the more the slope of the post-peak descending region will be and the lower of Froude number was prone to down degrade the seakeeping performance of the 'deep-V' catamaran due to the higher response of heave and pitch motion (Fitriadhy, Razali, & AqilahMansor, 2017) and (Vakilabadi et al, 2014).…”

Prediction of Propeller Performance Using Computational Fluid Dynamics Approach

“…Referring to the transport model discussed above, the viscosity has been taken into account that presents the high gradients near solid wall layers. Therefore, it is very important to have a sufficient amount the number of grid points in the boundary layers to properly capture the high gradient [21]. Here, an appropriate estimation of cell meshing size, for Navier-Strokes simulation, depends on the wall variable + to measure the viscosity effect region as written in Eq.…”

“…This paper presents a CFD simulation approach for the extension work from [21,22] to access the performance of propeller by KT, KQ, and Ƞ of the propeller. Here, a commercial CFD software, namely NUMECA Fine TM /Turbo v12.2 is utilized by grid generation, flow solver and post-processing capabilities.…”

A new phenomenon in interference effect on catamaran dynamic response

“…The Froude number of 0.4 was also introduced as the situation in which lowering the lateral spacing notably enlarges the drag force [33]. Similarly in the case of encountering sea waves, the reduction in hull lateral separation intensifies dynamic trim and sinkage [34]. Or even when there is a relative motion between two neighboring bodies, the slower one experiences stronger hydrodynamic loads as well as greater trim and sinkage due to the interaction [35].…”