The use of computational fluid dynamics to aid cost-effective hydrodynamic design of autonomous underwater vehicles

The missions being proposed for autonomous underwater vehicles (AUVs), by both marine scientists and industry, are becoming increasingly complex and challenging. In order to meet these demands the next generation of AUVs will need to be faster, to operate for longer durations, and to be more manoeuvrable than existing vehicles. It is therefore vital that the hydrodynamic forces and moments acting on a self-propelled manoeuvring AUV can be predicted accurately at the initial design stage. In order to achieve this, the use of a computational-fluid-dynamics-based analysis is suggested. The approaches developed are predominantly steady state and suitable for running on a workstation personal computer using a commercial software licence. It is estimated that the proposed simulations would take a competent user less than 1 month for a new concept design. The total cost of these simulations is significantly lower than the cost of building a model and having it commercially tested to capture the same level of detail for the resistance, propulsion, and manoeuvring performance. Based on the validation studies presented, it is estimated that on a 2 x 10(6) element structured mesh a competent user should be able to predict hydrodynamic forces to within at least 10 per cent and moments to within 20 per cent of in-service performance.