Study of a method for calculating boundary layer influence coefficients of ship and boat propelled by water-jet

Aiming at the problem that the boundary layer influence coefficients of waterjet propulsion ship are difficult to calculate, a method based on integral operation is proposed. The boundary layer influence coefficients are dealt with as a variable in this method. By solving the balance equation of propulsion pump absorbed power and engine power, the water flow of propulsion system is obtained. Then the value of effective inlet thickness of waterjet propulsion system is calculated based on the theorem of flow continuous. Through integral operation, treating the effective inlet thickness as the boundary condition, the analytical calculation expressions are ultimately derived. The boundary layer influence coefficients of certain waterjet propulsion ship are checked, and the trend of which under a certain power changing with ship speed is simulated to verify the correctness and effectiveness of this method.