The aim of the paper is to propose a groundbreaking method for the aerodynamic optimization design of the bioinspired wing with leading-edge tubercles. An emphasis on the optimization design of the spanwise waviness in the leading edge for delaying stall and increasing lift from the aerodynamic performance perspective has been laid in this study. For the conversion of the wavy configuration, the form parameterized approach using F-spline curves has been used to produce more variants of the leading-edge tubercles. Numerical investigations of flow characteristics which are performed using CFD computations have been used to validate the numerical scheme with experimental data. The combination of Non-dominated Sorting Genetic Algorithm II and Response Surface Method based Kriging Model has been adopted as the aerodynamic optimization strategy. As consequence, the three main components of the optimization process are incorporated into the establishment of the aerodynamic optimization design system for the bio-inspired airfoil with leading-edge tubercles. The four optimal airfoils respectively which increases the stall angle as well as the lift have been obtained in contrast to the smooth wing. The optimized bio-inspired design of this kind can be applied to flow-controlled devices for improving the efficiency of a particular operating mechanism.

In this paper, a comprehensive computational modeling study of the unsteady aerodynamic environment around a warship with a helicopter is performed. An experimental validation exercise is also conducted, comparing computational fluid dynamics (CFD) results of the airwake calculated for a reduced-scale model of the isolated Landing Helicopter Assault (LHA) model with high-quality particle image velocimetry experimental data provided by the NASA AMES Research Center. Comparisons of the results generally obtain agreement, indicating that the CFD numerical method is able to resolve the large-scale turbulent airflow. Building on this, a numerical simulation of a real Robin helicopter, immersed in the unsteady airwakes of a full-scale Amphibious Assault Ship (AAS), is performed. The aerodynamic simulation of the influence on the coupled airflow of warship–helicopter is explored and compared with that of the solitary ship airflow field and the superposition airwakes, where the vortex patterns and pressure on the ship surface, as well as the velocity distribution, are circumvented. As a further step, dynamic landing analysis of the airflow field for a shipborne helicopter is implemented at an important location through the landing path for headwind. The aerodynamic characteristics of a helicopter during a flight deck landing are also explored for the unsteady ship airwakes impacting on rotor force during shipboard landings. In addition, different shipboard landing paths of the helicopter are comparatively investigated for obtaining an optimal landing path decision. The present study demonstrates an effective aerodynamic analysis and robust numerical approach, which creates a solid foundation supporting further alternative evaluations of ship airflow fields.

In this article, an innovative hydrodynamic optimization design of bulbous bow hull-form under various service conditions resulting from the slow steaming of container vessel is presented, improving the overall performances for the real multi-variant usage situations more practical than the single specification of design, which includes both numerical computation and experimental validation. Effects of slow steaming–based statistical analysis of the actual operative occurrence during the lifetime is conducted, obtaining a combined probability density distribution of speed and displacement ushering in the evaluation of objective function. Three main component elements of the hydrodynamic optimization procedure that comprises parametric design of bulbous bow hull-form variation part, hydrodynamic numerical solver part, and optimization technique part are established and integrated. The proposed optimization process is subsequently applied to find the optimal bulbous bow of a container carrier for the hipping demand of different speeds and displacement distributed utilization, reducing significantly total conditions resistance of the hull, on a higher level decreasing the operative cost as well as gas emissions of the ship. Finally, there is an experimental campaign carried out between the optimal and original models to validate the numerical optimization computations. The compared investigation has provided a good agreement from the perspective of both numerical and experimental studies, as a result confirming the success of the present optimization framework and the utility value of the proposed optimization consideration on various service conditions during ship design stage.

The wake behind a single-screw ship contains both non-uniform axial momentum and near-hub swirl-related kinetic-energy loss. This study investigates a combined pre-duct and propeller boss cap fins (PBCF) configuration using unsteady Reynolds-averaged Navier–Stokes simulations coupled with the volume-of-fluid method and a sliding-mesh approach. A local wake-energy diagnostic framework is established by coupling axial momentum utilization, circumferential kinetic-energy proportion, non-axial kinetic-energy density, and positive-contribution statistics. Based on this framework, the complementary interaction between the duct-induced axial momentum enhancement and PBCF-induced near-hub swirl attenuation is clarified, and the sensitivity of the duct outlet diameter, chord length, axial position, and duct angle of attack is quantitatively ranked. The Duct-PBCF configuration increases the near-hub axial momentum utilization by approximately 9.1% and 5.0% at sections S2 and S3, respectively, compared with the bare propeller. It also reduces the circumferential kinetic-energy proportion by about 14.96% at S2 compared with the duct-only configuration. Among the duct parameters, the overall sensitivity follows A > D > X > L, with normalized weights of 0.36, 0.28, 0.21, and 0.14, respectively. Within the tested range, Dd/Dd,0 = 0.9 yields the largest efficiency improvement of approximately 3.2%, whereas a moderately positive duct angle of attack improves the thrust–torque balance. These results indicate that the Duct-PBCF design should be formulated as a multi-objective matching problem rather than as the optimization of a single performance index, involving propulsive performance, axial momentum enhancement, and vortex-energy reduction.