The Experts below are selected from a list of 2955 Experts worldwide ranked by ideXlab platform
Hiromichi Akimoto - One of the best experts on this subject based on the ideXlab platform.
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numerical analysis of righting moment for Heeling of a wing with Heel Angles in the surface effect
Journal of Marine Science and Technology, 2014Co-Authors: Makoto Kanehira, Hiromichi AkimotoAbstract:A wing-in-surface-effect-ship (WISES) is a high-speed transportation system that utilizes the enhanced lift-to-drag ratio which occurs in the proximity of the water surface. Unlike conventional aircraft and ships, a WISES experiences a righting moment against Heeling from the surface. In this study, we analyzed the flow around a wing that has Heel Angles in the surface effect using Reynolds-averaged Navier–Stokes (RaNS) simulations and experiments. We compared our numerical results with the measurements obtained in the wind tunnel tests to confirm the validity of the computational approach under several conditions. To detect the righting moment for Heeling without the effect of a boundary layer, we implemented a towing tank experiment and compared the results. In the towing tank experiment, we towed a wing model above flat plates in the water. Our results showed that a righting moment is generated for a wing that has Heel Angles in the surface effect. The righting moment is not proportional to the Heel Angle. In addition, the moment increases with decrease of the trailing edge altitude. Furthermore, we found that the addition of endplates enhances the righting moment.
Makoto Kanehira - One of the best experts on this subject based on the ideXlab platform.
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numerical analysis of righting moment for Heeling of a wing with Heel Angles in the surface effect
Journal of Marine Science and Technology, 2014Co-Authors: Makoto Kanehira, Hiromichi AkimotoAbstract:A wing-in-surface-effect-ship (WISES) is a high-speed transportation system that utilizes the enhanced lift-to-drag ratio which occurs in the proximity of the water surface. Unlike conventional aircraft and ships, a WISES experiences a righting moment against Heeling from the surface. In this study, we analyzed the flow around a wing that has Heel Angles in the surface effect using Reynolds-averaged Navier–Stokes (RaNS) simulations and experiments. We compared our numerical results with the measurements obtained in the wind tunnel tests to confirm the validity of the computational approach under several conditions. To detect the righting moment for Heeling without the effect of a boundary layer, we implemented a towing tank experiment and compared the results. In the towing tank experiment, we towed a wing model above flat plates in the water. Our results showed that a righting moment is generated for a wing that has Heel Angles in the surface effect. The righting moment is not proportional to the Heel Angle. In addition, the moment increases with decrease of the trailing edge altitude. Furthermore, we found that the addition of endplates enhances the righting moment.
Movahedi Fateme - One of the best experts on this subject based on the ideXlab platform.
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Numerical analysis of side hull configuration in Trimaran
'Scipedia S.L.', 2019Co-Authors: Heidari Milad, Razaviyan Zahrapanah, Yusof Feizal, Mohammadian E., Alias, Azil Bahari, Akhbari M.h., Akbari A., Movahedi FatemeAbstract:A trimaran is a multihull vessel designed to reduce wave-making resistances at high speeds. Optimization of the hull shape increases hull efficiency and speed of a vessel. The behavior of a ship is generally analyzed through numerical methods to save time and reduce high expenditures as compared to experimental methods. Although wide ranges of studies have investigated the hydrodynamic behavior of a vessel, the effect of trim Angle, yaw Angle, and Heel Angle of side hulls on hydrodynamic behavior of a trimaran has not been addressed properly. In the present study, a trimaran was modeled using computer-aided design software. Dimensions of the computational domain and boundary conditions were applied. Furthermore, mesh convergence was carried out. The accuracy of the method was validated. Analyses are based on the finite volume method. The analysis is carried out to obtain the resistance of side hulls and its effect on total trimaran resistance, effect of speed on hulls vessel resistance, wave patterns generated by the vessel at different trim and yaw Angles, effect of trim, Heel and yaw Angles on side hull and total resistance of trimaran, the wetted surface at different trim, yaw, and Heel Angles, shape of free surface between the hulls, and the optimal position and trim Angle of side hulls relative to the main hull. This computational analysis represents a step in quantifying the role of the trim, Heel and yaw Angles of side hulls on hydrodynamic characteristics of trimaran in calm water. The worth of information from the present study may express the importance of the factors that could reduce the total resistance of a trimaran.Peer Reviewe
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Numerical analysis of side hull configuration in Trimaran
2019Co-Authors: Heidari Milad, Razaviyan Zahrapanah, Yusof Feizal, Mohammadian E., Akhbari M.h., Akbari A., Alias Azil, Movahedi FatemeAbstract:A trimaran is a multihull vessel designed to reduce wave-making resistances at high speeds. Optimization of the hull shape increases hull efficiency and speed of a vessel. The behavior of a ship is generally analyzed through numerical methods to save time and reduce high expenditures as compared to experimental methods. Although wide ranges of studies have investigated the hydrodynamic behavior of a vessel, the effect of trim Angle, yaw Angle, and Heel Angle of side hulls on hydrodynamic behavior of a trimaran has not been addressed properly. In the present study, a trimaran was modeled using computer-aided design software. Dimensions of the computational domain and boundary conditions were applied. Furthermore, mesh convergence was carried out. The accuracy of the method was validated. Analyses are based on the finite volume method. The analysis is carried out to obtain the resistance of side hulls and its effect on total trimaran resistance, effect of speed on hulls vessel resistance, wave patterns generated by the vessel at different trim and yaw Angles, effect of trim, Heel and yaw Angles on side hull and total resistance of trimaran, the wetted surface at different trim, yaw, and Heel Angles, shape of free surface between the hulls, and the optimal position and trim Angle of side hulls relative to the main hull. This computational analysis represents a step in quantifying the role of the trim, Heel and yaw Angles of side hulls on hydrodynamic characteristics of trimaran in calm water. The worth of information from present study may express the importance of the factors that could reduce the total resistance of a trimaran
Alan Wilson - One of the best experts on this subject based on the ideXlab platform.
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relationship of foot conformation and force applied to the navicular bone of sound horses at the trot
Equine Veterinary Journal, 2010Co-Authors: E Eliashar, M. P. Mcguigan, Alan WilsonAbstract:Summary Reasons for performing study: Collapsed Heels conformation has been implicated as causing radical biomechanical alterations, predisposing horses to navicular disease. However, the correlation between hoof conformation and the forces exerted on the navicular bone has not been documented. Hypothesis: The Angle of the distal phalanx in relation to the ground is correlated to the degree of Heel collapse and foot conformation is correlated to the compressive force exerted by the deep digital flexor tendon on the navicular bone. Methods: Thirty-one shod Irish Draught-cross type horses in routine work and farriery care were trotted over a forceplate, with 3-dimensional (3D) motion analysis system. A lateromedial radiograph of the right fore foot was obtained for each horse, and various measurements taken. Correlation coefficients were determined between hoof conformation measurements and between each of these and the force parameters at the beginning (15%) of stance phase, the middle of stance (50%) and at the beginning of breakover (86% of stance phase). Significance was defined as P<0.05. Results: The force exerted on the navicular bone was negatively correlated (P<0.05) to the Angle of the distal phalanx to the ground and to the ratio between Heel and toe height. This was attributed to a smaller extending moment at the distal interphalangeal joint. There was not a significant correlation between the Angle of the distal phalanx and the degree of Heel collapse, and Heel collapse was not significantly correlated to any of the force parameters. Conclusions: Hoof conformation has a marked correlation to the forces applied to the equine foot. Heel collapse, as defined by the change in Heel Angle in relation to toe Angle, appears to be an inaccurate parameter. The forces applied on the foot are well correlated to the changes in the ratio of Heel to toe heights and the Angles of the distal phalanx. Potential relevance: Assessment of hoof conformation should be judged based on these parameters, as they may have clinical significance, whereas parallelism of the Heel and toe is of less importance.
Meiqi Wang - One of the best experts on this subject based on the ideXlab platform.
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A numerical investigation on the effect of symmetric and asymmetric flooding on the damage stability of a ship
Journal of Marine Science and Technology, 2020Co-Authors: Xinlong Zhang, Zhuang Lin, Dengke Liu, Zhanwei Pang, Meiqi WangAbstract:Reliable analysis of the flooding process and motion responses onboard a damaged ship is extremely significant for assessing the remaining survivability and improving the damage stability. This study implemented the Unsteady Reynold-Average Navier–Stokes (URANS) solver to monitor the three degrees of freedom (DOF) motion, investigating the effect of symmetric and asymmetric flooding on the damage stability. The Volume of Fluid (VOF) method was applied to visualize the flooding process and capture the complex hydrodynamics behavior. Additionally, basic governing equations of fluid flow and free motion are detailed. The simulation results show that in the same damage condition, the transverse asymmetric flooding results in a larger Heel Angle. However, for the pitch and heave motion, there are small differences between the symmetric flooding and asymmetric flooding. Therefore, if the damaged ship is predicted to keep afloat, the transverse symmetric flooding should be guaranteed as much possible. In this case, the flooding water can flow from the damaged side to the intact side. Consequently, the damaged ship can maintain a relatively stable floating state, decreasing the risk of capsizing due to the excessive Heel Angle. Finally, all the numerical simulation cases are performed on the commercial software CD Adapco STAR-CCM+.