Papers by Keyword: Hydrodynamics

Abstract: The proliferation of beach renovation is affecting the change of the landform of the coast and threatening the ecological environment. Therefore, it is necessary to assess the impact on the environment after the beach is transformed. The survey area is located near the Shipu fishing port in the south of Ningbo City, Zhejiang Province. Based on the Delft-3D grid nesting model and wave-fluid coupling model, the astronomical tide and hydrodynamic environment of the 30 days before the construction were simulated. After the beach was rebuilt and sand was added and the spur dike was added, the astronomical tide and hydrodynamic environment were again simulated. Finally, based on the simulated data, the water level, velocity field, effective wave height distribution, and siltation and siltation of Xinhe Beach were obtained. Xinhe Beach's environmental damage risk indicators can be evaluated based on water level, velocity field, effective wave height direction and sediment erosion and deposition. Artificial sanding and construction of spur dikes will change the hydrodynamics and scouring and siltation of Xinhe Beach, but have little effect on the coastal terrain and ecological environment.

Abstract: In this work a computational model is presented in order to simulate the trajectory of objects near the Ilhabela island region, in São Paulo coastline, Brazil. The MOHID platform (MOdelagem HIDrodinâmica - Hydrodynamics Modelling) was used with the downscalling technique used to obtain local hydrodynamic currents at local scale. Two different applications are tested, the first is the hypothetical trajectory of a dead cetacean specimen drifting that could have happened in fact if it was not arrested to a more adequate spot near Ilhabela island in November, 2017, and the second is the simulation for the drift of floating objects that resulted from an accidental release of containers at the Port of Santos in August, 2017. The use of these technologies has great potential for researchers interested to simulate different drift occurrences near the Brazilian costal region.

Abstract: Response characteristics in the opening and closing operations of the micro magnetic fluid diaphragm mechanism by the alternating magnetic field are described. The micro magnetic fluid diaphragm mechanism was composed of a ring shaped permanent magnet and kerosene-based magnetic fluid. The driving principle of micro magnetic fluid device was based on the surface phenomena of magnetic fluid adsorbed on a permanent magnet. The opening and shutting time of diaphragm mechanism in the alternating magnetic field was measured by high-speed video camera system. The details of magnetic fluid surface response in the opening and closing operations of magnetic fluid hole were revealed experimentally.

Abstract: Responses of a magnetic fluid interface adsorbed on a small permanent magnet in water container subjected to an alternating magnetic field were studied with a high-speed video camera system. The directions of the external alternating magnetic field were parallel and anti-parallel to that of the permanent magnet. It was found that the interface of water-magnetic fluid responds to the external alternating magnetic field in elongation and contraction with Rosensweig instability at the interface. Frequency characteristics of the interface response of water-magnetic fluid system subjected to alternating magnetic field were revealed over a wide frequency band experimentally.

Abstract: Numerical simulation of the motion of a viscous incompressible nonisothermal liquid in an open rectangular cavity with a glance of heterogeneity phase characteristics is performed. The hydrodynamic pattern of moving liquid has been obtained. Temperature profiles for solid and liquid phases have been received. The model parameters influence on the motion of the heat carrier and the distribution of temperatures in two phases have been studied.

Abstract: Fish Swimming in MPF (Media and/or Paired Fin) mode has unique hydrodynamic characters and special application in resource exploration underwater. Inspired of the flexible shape and motion of undulating fin of “Nilotic Ghost” fish, a Hydraulic-driven Bionic Undulating Robot (HBUR) is developed and studied in the paper based on CFD method, to investigate the flexible characteristics of shape adaptation and hydrodynamics of HBUR fin, which has great significance for the propelling safety of HBUR underwater. In this paper, a mathematical model is brought forward to indicate the undulating motion of HBUR, which is formed by sequentially and periodically swing motions of Hydraulic Swing Actors (HSAs), and then the CFD method is introduced to calculate the hydro-forces when undulating shape of HBUR fin are distorted, because of distraction underwater. Results show that HBUR could produce propelling forces even when some of the HSAs are restricted from swinging, and shape adaptation ability of different part on HBUR fin is different, where the middle part is worse than the two sides. The propelling forces generated by undulating motion the rest of HBUR fin could be used to get the underwater robot out of trouble itself, and then undulating shape will restore to normal state.

Abstract: The paper presents the numerical research of conjugate heat exchange and hydrodynamics in the motion of viscous fluid in the technological elements of energy systems (cavities) in the consideration of its damage. The hydrodynamic figure of the motion viscous fluid and its temperature fields for solid and fluid phases obtained. The model parameters influence on the motion of the heat carrier and the distribution of temperatures in two phases have been studied. The impact of dynamic parameters and geometrical characteristics for the formation of contours generating craters studied.

Abstract: The water tunnel and wind tunnel test carried on the arrow aims to have a better understanding of the hydrodynamics performance of arrows and to improve the technical knowledge of the archery movement Through the experimental research, we can draw conclusions as follows: within the range of angle of attack ( -6°---6°), the arrow can keep the state of attached flow: The state of flow of the arrow with spiral plastic pinna is better than that of arrow with straight one; Within the experimental angle of attack, the lift coefficient Cy will become larger with the pitching moment coefficient Mz getting smaller with the increase of the angle of attack. The arrow has the vertical static stability; with or without arrow feather will have great impact on lift force Y and pitching moment coefficient Mz; the feather rolling will have some impact on lift coefficient Cy, The arrow feather is the main components to produce lift force Y and to give the arrow body relatively great static stability.

Abstract: Countercurrent cyclones have been quite widely applied in various industries [1-12]. In this paper, on the example of classical construction of countercurrent cyclone considers the impact of the conical nozzle on the exhaust pipe to the gas-dynamic picture and efficiency dedusting.

Abstract: This study aims to investigate the hydro- and aerodynamic characteristics of arrows as understood within the field of archery and to contribute to theoretical knowledge, upon which archery techniques are based. The water tunnel and wind tunnel are used to test different arrows consisting of four famous brands.The results showed that when the angles of attack from -6°to 6°, the arrow remained in the state of attached flow. Arrows that had spiral plastic fletches demonstrated better states of flow than arrows with straight fletches. Within the range of the experimental angles of attack, the coefficients of lift increased, while the coefficients of pitching moment decreased when the angle of attack increased. The arrows showed static stability in the longitudinal direction. Arrow fetches also demonstrated considerable influence on the lift and pitching moment. The rolling of the arrows caused the change of the coefficient of lift. Based on the results, it can be concluded that arrow fetches are the major contributors to the arrows’ flight stability.