Visualisation of the horseshoe vortex around the submarine sail


Visualisation of vortices around a submarine during a manoeuvre


MARIN assists clients in improving the hydrodynamic performance of submarines


Numerical computations are increasingly used to assess submarine designs. Serge Toxopeus, s.toxopeus@marin.nl


Several navies around the world are working on new submarine designs. To assess and improve the hydrodynamic performance of these boats, MARIN has performed numerous computational studies with the viscous-flow solver ReFRESCO. With these computations, the resistance or powering performance of the submarine can be obtained. Additionally, forces and moments during manoeuvres are derived.


One recent example is a numerical study that looked to improve the junction between the submarine hull and the sail in order to reduce adversary effects of the horseshoe vortex that develops near the junction [1]. In this project several cuffs or fillets were designed and their influence on resistance and wake quality was quantified. By using a proper cuff, a 2% reduction in resistance


22 report


could be obtained. As an additional benefit, the cuff can also be used to store extra equipment, such as diver propulsion devices. Furthermore, the study demonstrated that rounding the tip of the sail can also reduce the resistance substantially.


Another project concerns the analysis of a generic submarine to investigate the influence of the bow shape on manoeuvring perfor- mance. The bow shape was varied to obtain the desired transit speeds while sailing at the surface [2], but the influence on the manoeu- vring characteristics needed to be quantified. With ReFRESCO, an extensive series of computations for the fully appended and self-propelled submarine for pure drift, yaw and combined motion was performed. From the results, manoeuvring coefficients were derived and used in the fast-time submarine


manoeuvring prediction program SAMSON to estimate the turning, course keeping and yaw checking abilities.


The projects MARIN has performed using ReFRESCO have clearly convinced clients that CFD is an indispensible, valuable and accurate tool to analyse, understand and improve the hydrodynamic performance of submarines.


1. Toxopeus, S.L., Kuin, R.W.J., Kerkvliet, M., Hoeijmakers, H. and Nienhuis, B., “Improvement Of Resistance And Wake Field Of An Underwater Vehicle By Optimising The Fin-Body Junction Flow With CFD”, OMAE ASME 33rd International Conference on Ocean, Offshore and Arctic Engineering, San Francisco, CA, 2014.


2. Overpelt, B. and Nienhuis. B., “Bow Shape Design For In- creased Surface Performance Of An SSK Submarine”, RINA Warship 2014: Naval Submarines & UUV’s, Bath, UK, 2014


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24