The utilization of ocean renewable energy, especially wave energy, is of great significance in ocean engineering. In this study, a three-dimensional numerical wave tank was established to simulate the wave-float interaction based on the Reynolds-averaged Navier–Stokes equations and the Realizable K-Epsilon Two-Layer turbulence model was applied. Firstly, convergence studies with respect to the mesh and time step were carried out and confirmed by the published analytical and numerical data. Then, the resonance condition of a particular float was solved by both numerical and analytical methods. The numerical and the analytical results are mutually verified in good agreements, which verify the reliability of the analytical process. Furthermore, a wave energy converter (WEC) consisting of a single float without damping constant was adopted, and its hydrodynamic performance in different wave conditions was investigated. It was found that the damping factor can affect the motion response of the float and the wave force it receives. Under a certain wavelength condition, the WEC resonates with the wave, at which the wave force on the float, displacement of the float and other parameters reach a maximum value. Finally, the influence of linear damping constant on the power take-off (PTO) was studied. The results show that the damping factor does not affect the wave number turning point of the optimal damping constant.
A 2D numerical model was established to investigate vortex induced vibration (VIV) for submerged floating tunnel (SFT) by solving incompressible viscous Reynolds average Navier-Stokes equations in the frame of Abitrary Lagrangian Eulerian (ALE). The numerical model was closed by solving SST k-ω turbulence model. The present numerical model was firstly validated by comparing with published experimental data, and the comparison shows that good achievement is obtained. Then, the numerical model is used to investigate VIV for SFT under current. In the simulation, the SFT was allowed to oscillate in cross flow direction only under the constraint of spring and damping. The force coefficients and motion of SFT were obtained under different reduced velocity. Further research showed that Reynolds number has not only a great influence on the vibration amplitude and ‘lock-in’ region, but also on the force coefficients on of the SFT. A large Reynolds number results in a relatively small ‘lock-in’ region and force coefficient.
In the 13th five-year planning, the pumped storage power stations have speeding up. A large number of pumped storage power stations will been installed. The current development of modern pump storage plants aims towards a higher flexibility and stability in operation, an extended operation range of the hydraulic machine. The stability of pump turbine has been paid more and more attention in the industry.
Hydraulic pressure pulsation is very important for the stability of pump turbine. For pump turbine, the pressure pulsation on vane-less area between guide vane and runner blade is very important. It is the fundamental source of unit stability and the direct embodiment of rotational and static interference.
This paper analyses the special pressure pulsation in the vane-less area of pump turbine, focusing on the pressure pulsation of one time rotating frequency and two times rotating frequency.
The amplitude and frequency of pressure pulsation and the source of pressure pulsation induced by this special frequency are analysed and detected from the perspective of numerical and model test. By optimizing the design of the runner, the pressure pulsation of that particular frequency is eliminated.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.