-Drift current induced by wind and waves is investigated with phase-averaged Navier-Stokes equation in which the Reynolds stress is closed by k-ε model. The governing equations are solved by the finite volume method ...-Drift current induced by wind and waves is investigated with phase-averaged Navier-Stokes equation in which the Reynolds stress is closed by k-ε model. The governing equations are solved by the finite volume method in a system of nonorthogonal coordinates which is fitted to the phase-averaged wave surface. The predicted drift current is fairly reasonable and the drag coefficient of sea-surface predicted with the newly developed interface conditions shows good agreement with previous measurements when breaking waves do not exist.展开更多
We numerically simulate the generation of an optical frequency comb（OFC） in a microring based on the traditional Si_3N_4 strip waveguide and a temperature compensated slot waveguide.The results show that OFCs are su...We numerically simulate the generation of an optical frequency comb（OFC） in a microring based on the traditional Si_3N_4 strip waveguide and a temperature compensated slot waveguide.The results show that OFCs are susceptible to temperature with strip waveguide while they can keep stable when temperature changes 10 Kin either low-Q（10-5） or highQ（10-6） microcavity with the well-designed slot waveguide,which has great superiority in practical applications where the temperature drift of the cavity due to the intense pump or surrounding change is unavoidable.展开更多
This paper proposes an online power system voltage stability index(PVSI Online)that quantifies power system voltage stability in real time between an AC network and LCC HVDC using only local measurements.Previous meth...This paper proposes an online power system voltage stability index(PVSI Online)that quantifies power system voltage stability in real time between an AC network and LCC HVDC using only local measurements.Previous methods relied on using telecommunications to inform a change in a predetermined AC network model.The proposed method uses local measurements of voltage and current from the HVDC using a newly developed,numerically robust technique called Moving Window Covariance to detect a change in the AC network in real time.These network parameters are fed to a newly devised index that accurately models and captures the dynamics of the interaction between an LCC HVDC and AC network.The index is used to quantify stability,but also to advise network operation.In an onset of instability due to network degradation,the proposed index can provide a power order value for the HVDC to restore stability.All as a self-contained module that can be implemented within a HVDC scheme.展开更多
文摘-Drift current induced by wind and waves is investigated with phase-averaged Navier-Stokes equation in which the Reynolds stress is closed by k-ε model. The governing equations are solved by the finite volume method in a system of nonorthogonal coordinates which is fitted to the phase-averaged wave surface. The predicted drift current is fairly reasonable and the drag coefficient of sea-surface predicted with the newly developed interface conditions shows good agreement with previous measurements when breaking waves do not exist.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61435002,61527823,and 61321063)
文摘We numerically simulate the generation of an optical frequency comb（OFC） in a microring based on the traditional Si_3N_4 strip waveguide and a temperature compensated slot waveguide.The results show that OFCs are susceptible to temperature with strip waveguide while they can keep stable when temperature changes 10 Kin either low-Q（10-5） or highQ（10-6） microcavity with the well-designed slot waveguide,which has great superiority in practical applications where the temperature drift of the cavity due to the intense pump or surrounding change is unavoidable.
文摘This paper proposes an online power system voltage stability index(PVSI Online)that quantifies power system voltage stability in real time between an AC network and LCC HVDC using only local measurements.Previous methods relied on using telecommunications to inform a change in a predetermined AC network model.The proposed method uses local measurements of voltage and current from the HVDC using a newly developed,numerically robust technique called Moving Window Covariance to detect a change in the AC network in real time.These network parameters are fed to a newly devised index that accurately models and captures the dynamics of the interaction between an LCC HVDC and AC network.The index is used to quantify stability,but also to advise network operation.In an onset of instability due to network degradation,the proposed index can provide a power order value for the HVDC to restore stability.All as a self-contained module that can be implemented within a HVDC scheme.
