Optimal shape design of multi-element trawl-doors using local surrogate models

• Here, we present an optimization algorithm for the shape design of trawl-door shapes using computational fluid dynamic (CFD) models.
• The proposed approach uses a low-order response surface approximation in place of expensive CFD models.
• This reduces the number of evaluations of the accurate CFD model during the optimization.
• Demonstration examples show that multi-element trawl-door shapes can be designed with few iterations of the algorithm.

Trawl-doors have a large influence on the fuel consumption of fishing vessels. Design and optimization of trawl-doors using computational models are a key factor in minimizing the fuel consumption. This paper presents an optimization algorithm for the shape design of trawl-door shapes using computational fluid dynamic (CFD) models. Accurate CFD models are computationally expensive. Therefore, the direct use of traditional optimization algorithms, which often require a large number of evaluations, may be prohibitive. The proposed approach is iterative and uses low-order local response surface approximation models of the expensive CFD model, constructed in each iteration, to reduce the number of evaluations. The algorithm is applied to the design of a multi-element trawl-doors, involving up to four design variables controlling the angle of attack and the slat and flap position and orientation. The results show that a satisfactory design can be obtained at the cost of a few iterations of the algorithm.