The effect of appendages on the hydrodynamic characteristics and movement of a submerged body at shallow depth

Abstract

Modern autonomous underwater vehicles have a complex hull shape with superstructures, rudders and other elements located on the surface. The study carried out an experimental and theoretical analysis of the influence of protruding parts in the form of a wing-shaped superstructure located at the bow end, horizontal and vertical stern rudders on the nature of body movement in the near-surface water environment and its hydrodynamic characteristics. For the first time, the dependences of the relative vertical displacement of a body arising under the influence of a lifting force were obtained experimentally on the basis of an experimental tank, and the trim angles of the model were determined for various values of Fr numbers. Using the proposed numerical model, the pressure fields that form around the body during its movement are calculated, the nature of wave formation on the water surface is established, and the dependences of the coefficients of lifting force and trimming moment are obtained. The results obtained were compared with data for a similar body model, without protruding parts. It was found that when a model with a more complex body architecture moved, the lifting force and, accordingly, the vertical movement of the body increased. There was also a significant increase in the values of the trimming moment and, accordingly, the trim angles of the model, which is obviously associated with an increase in the area of the wetted surface.