A new method of reducing the resistance of submarines is presented, which consists in installing special circular recesses on its surface in the stern. It is found that during the movement, in the recesses there is a macro-vortex flow, in which pressure decreases significantly. This phenomenon affects the characteristics of the boundary layer and in general the pressure distribution on the surface of the hull, i. e. the resistance of the submarine. Using the methods of computational fluid dynamics, the influence of the number and size of the recesses at their fixed location on the resistance of two types of "Lira" and "Gepard" submarines is investigated. The results show that the decrease in resistance increases with increasing Reynolds number and reaches 6 % for "Lira" with 4 recesses with a diameter of d=0.01 D at Re=1.55. 108 and 2 % at Re=1.35. 108 for "Gepard" with 7 recesses with a diameter of d=0.01 D. The effect of the number of cells of the computational grid on the results of calculations in the Flow Simulation (USA, France, Canada) and Flow Vision (Russian Federation) software packages was also studied. The effect of resistance reduction obtained in both software packages is approximately the same, but the absolute values differ due to the small number of cells in Flow Vision, which is due to the limited capabilities of the used 2nd version of this complex. There was also a slight effect of resistance reduction on the model of the "Persia-110" (Iran) submarine with recesses during towing tests in the research basin at significantly lower Reynolds numbers. Unlike most resistance reduction means, the use of this method does not require significant changes in the design of the housing. This makes it possible to use it both on new facilities and on facilities that have already been commissioned

It is proposed to install on the wetted surface of the poorly streamlined body: on one a profiled recess, and on the second step. The first device changes the pressure distribution on the surface of the selected object. In the middle recess, a vortex motion is created, in the middle of which the pressure is lowered, which makes it possible to reduce the thickness of the boundary layer. The main purpose of the second device is to reduce the suction effect of water during acceleration of the object. Thus, the resistance force decreases, which means that it is much easier and faster to pick up speed and maintain it for a long time. After studying two methods of reducing resistance, it is proposed to evaluate the effectiveness and the prospect of using the above methods simultaneously with the air lubrication method. The Air Lubrication technology is based on blowing air bubbles out under the hull of the vessel. The air bubble distribution across the hull surface reduces the resistance creating a sublayer between the body of the object and water. These studies were conducted in the Flow Vision software package to obtain visualization and calculations, which confirm that the use of the proposed methods makes it possible to reduce the resistance of the body when it is moved in a liquid.

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