Numerical study of effects of geometric parameters on the flow and cavitation characteristics inside conical nozzle of autonomous underwater vehicles

Abstract

The geometric parameters (ratio of orifice's length to diameter, conical angle, and inner-wall roughness) of conical nozzle are investigated via computational fluid dynamic method to reveal the effect on the flow and cavitation characteristics. The variation of geometric parameters affects the distribution of the static pressure and the drag force, which in turn affects the mass flow rate at the outlet. The results indicate that the conical angle plays a dominant role in effecting the flow and cavitation characteristics. The higher the intensity of cavitation, the more notable the effect of geometric parameters on cavitation characteristics.

Numerical investigation of non-Newtonian inelastic flows through conical nozzles

“…In the first phase, a two-step predictor-corrector technique is utilized to compute the u * components by providing the initial velocity and pressure fields. The Choleski technique is utilized to calculate the pressure differences during the second phase (𝑃 𝑛+1 − 𝑃 𝑛 ) based on u * [14][15][16][17]. Finally, the velocity field 𝑢 𝑛+1 is evaluated when, 𝑢 * and pressure difference (𝑃 𝑛+1 − 𝑃 𝑛 ) are adopted by employing the Jacobi iteration [15,21].…”

“…By utilizing the scaling 𝑅𝑒 = 𝜌 𝑈𝐿 𝜇 , on the other hand, the equation may also be expressed in terms of the non-dimensional groups of Reynolds numbers (Re), with (𝜌), (L), and (U) standing for the characteristic density lengths and velocities, respectively [15].Therefore, the non-dimensional form of equation 2 is…”

Numerical investigation of extensional flow through axisymmetric conical geometries: Finite element method

“…The characteristics of the geometry have a huge effect on the flow characteristics. The geometric parameters of the conical flow: the half-angle ( ), the ratio between the length to the diameter of the upstream section, and the ratio between upstream to downstream diameters are considered as characteristics of the conical geometry [14,15]. Under normal circumstances, the geometric parameters varying leads to a significant impact on mass flow rate [15].…”

“…The geometric parameters of the conical flow: the half-angle ( ), the ratio between the length to the diameter of the upstream section, and the ratio between upstream to downstream diameters are considered as characteristics of the conical geometry [14,15]. Under normal circumstances, the geometric parameters varying leads to a significant impact on mass flow rate [15]. Also, changes in the static pressure and drag force are correlated to the changes of geometric parameters [15].…”

“…Under normal circumstances, the geometric parameters varying leads to a significant impact on mass flow rate [15]. Also, changes in the static pressure and drag force are correlated to the changes of geometric parameters [15]. In the conical flow, the flow generates regions of near-sink flow for specific sets of Reynolds numbers [16,17].…”