In this paper, mathematical modeling of a small scale ducted-fan UAV is conducted, and the modeling results are compared with wind tunnel test. Wind tunnel test is performed and bunch of test data were acquired. A set of wind tunnel test data was categorized and approximated as mathematical functions. Mathematically modeled force and moments acting on the UAV are then compared with those of the wind tunnel data. A gradient-based algorithm is applied to extract trim states with respect to various flight conditions. Numerical analysis shows reasonable flight status with respect to airspeed. Nomenclature d C = drag coefficients of x, y, z axis D = the duct drag force h = the distance between the center of gravity and center of pressure of the duct   k  = the drag coefficient with various angle of attack L = the duct lift force l = the distance between aerodynamic center of control surface and center of gravity S = vehicle platform area d S = the duct area v = velocity vector of vehicle in the body fixed-frame i v = the induced velocity Fuselage z = the distance between the aerodynamic center and the center of gravity of vehicle

Autonomous ship technology, which includes real-time monitoring, satellite communication, and automatic navigation, is rapidly advancing. Despite significant research on single unmanned ships, there is a lack of studies on complex tasks, such as ship berthing using a swarm of autonomous tugboats. This review article provides an overview of various projects related to autonomous tugboats for ship berthing and discusses the research trends in the required technologies, including recognition, decision making, modeling, and control. We identify the areas that have been underexplored in existing studies and suggest future research directions to advance the field. Overall, this review contributes to a better understanding of the challenges and opportunities for the development of autonomous tugboats for ship berthing.

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An experimental study was carried out in order to investigate the influence of Reynolds number on the near-wake of an oscillating airfoil. An NACA 0012 airfoil was sinusoidally pitched at the quarter chord point, and is oscillated over a range of instantaneous angles of attack of ±6°. An X-type hot-wire probe was employed to measure the near-wake of an oscillating airfoil, and the smoke-wire visualization technique was used to examine the flow properties of the boundary layer. The

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