Resistance characteristics of submerged projectile with bow variation based on hull Envelope equation using steady RANS simulation

This paper investigates the influence of the forebody of a projectile-shaped model without appendages and propulsion system in a submerged condition. The commercial steady RANS code, ANSYS Fluent, was used to conduct the simulations, and the forebody was varied based on the Hull Envelope equation. From the results, the model with nf = 2.75 was the optimum design according to the bow efficiency coefficient. However, the model with a blunt form (nf = 1) produced the lowest drag because it had the least wet surface area. For models with high nf, a high accelerating flow led to a low-pressure condition after the impact of the fluid on the fore end. This soaring pressure difference caused a flow separation, and therefore the fullness of the forebody affected the fluid flow around the body: the alteration of pressure, the flow speed, and friction as the primary component of resistance.