CJR Propulsion, has developed accurate design tools to optimise propeller and sterngear technology for improved performance, fuel efficiency, longevity and reduced vibration, using computational fluid dynamics (CFD).
Using CFD software coupled with vortex lattice code, which has been developed in-house, CJR is able to analyse and solve problems relating to fluid flows; using numerical methods and algorithms to perform the complex calculations required to simulate the interaction between hull, propellers, appendages and the water.
The bespoke CFD program provides an excellent understanding of the fluid flow passed the hull and appendages below the waterline. This enhanced understanding allows CJR to significantly reduce the appendage drag – which contributes between 10% to 15% of the overall drag of the craft. This sort of improvement could equate to around a two knot increase in cruise speed on a high speed craft.
Our CFD simulations are also capable of providing information about the operating performance of a hull in calm water. Parameters such as the running trim angle, and hull resistance can be calculated. CJR can also calculate the optimum longitudinal center of gravity position for reduced drag.
The CFD simulations highlight areas of the hull where the flow separates from the hull surface. This is particularly important in the sterngear region.