Hydrodynamics of braided netting knotless

Abstract

Netting knotless represent fishing implements and aquaculture cages. These are mesh fabrics made of high-strength yarns without the use of knots. Polyamide and polyethylene fibers serve as the material. Nettings knotless fabrics are produced in special knitting factories that work in accordance with the technology of fixing cells. At the last stage of production, the products are subjected to heat treatment, which provides additional strength to the nettings. Such nets are superior to their nodular analogues. They are more reliable, the weight due to the lack of nodal connections is less, the risk of injury to fish is minimal, also the flow rate of such connections is better, and algae and other microorganisms do not grow to them. Netting knotless are widely used in the manufacture of cages, selective inserts of trawls, seines and traps. The article considers the application of a numerical method to determine the hydrodynamic characteristics of knotless netting using software developed by the authors. The schematization of the netting knotless was performed to create a mathematical model based on Navier-Stokes partial differential equations. The initial and boundary conditions for a given computational domain were established. The calculation was carried out on a regular computational grid using an implicit finite-difference scheme using methods of coordinate splitting, linearization of nonlinear equations with subsequent correction of nonlinear coefficients, and solution of the obtained tridiagonal systems by the run-through method. The results of numerical experiments are presented in the form of visualization of pressure on the surface of various mesh structures at different angles of attack.