3 results about "Robin boundary condition" patented technology

The present invention discloses a fluid-solid coupling numerical simulation method for the coupling of surface water and soft soil subgrade soil, including: setting the simulation time and time step, and inputting the collected surface water data and the physical property parameters of the subgrade soil into the simulation model; establishing the coupling action equation of surface water and soil: describing the movement of surface water through the Stokes equation including boundary conditions, describing the soil through the Biot equation, and coupling the Stokes equation and the Biot equation through the interface condition to obtain a coupling system; constructing the Robin boundary condition, and reconstructing and decoupling the coupling system through the Lagrangian-Eulerian method; ending the simulation when the simulation time is reached, and outputting the deformation displacement, seepage flow pressure and seepage flow velocity of the subgrade for judging the stability of the subgrade. The present invention solves the problems of difficulty in judging the stability according to the coupling action of surface water and soft soil subgrade and consuming a large amount of resources.

The application discloses a kind of based on multi-source heterogeneous data fusion and boundary self-adapting three-dimensional temperature field soft measurement method and system, method includes: obtaining infrared time series temperature field data and discrete thermocouple time series temperature data;Establish three-dimensional tetrahedral finite element grid model, and the solution domain is divided into the sub-region with independent thermal physical property parameters;Adaptive Robin boundary condition with virtual control gain is constructed, and the initial value of global three-dimensional simulation temperature field of current time step is obtained;Based on the pre-constructed spatial hierarchical index structure, the corresponding simulation temperature value at the position of discrete thermocouple is extracted;Temperature residual is calculated, and the equivalent thermal diffusivity of each sub-region is independently updated using asymmetric parameter identification law;The updated equivalent thermal diffusivity is fed back to the next iteration round, and when the set convergence condition is reached, the measured object three-dimensional transient temperature field and the identified thermal physical property parameters are output.The application improves the numerical stability of multi-source data assimilation solution.

The invention discloses an IGBT module periodic temperature fluctuation distribution calculation method, system, medium and equipment, and the method comprises the steps: building a frequency domain finite element thermal model according to an actual three-dimensional geometric structure and material characteristics of an IGBT module, and employing a Robin boundary condition to describe a heat transfer relation between the IGBT module and a radiator; a frequency domain loss model of the IGBT module is established, modeling is carried out on conduction loss and switching loss of an IGBT chip and an FWD chip, and a frequency domain expression of periodic loss is obtained through Fourier transform; and executing an iterative calculation process, solving a steady-state heat conduction equation based on the average loss, obtaining average temperature distribution to serve as reference temperature to be substituted into the frequency domain loss model, solving temperature fluctuation response corresponding to each order of harmonic wave in the frequency domain to obtain amplitude and phase angle of each time of temperature fluctuation, and performing frequency-time domain transformation to obtain a frequency-domain loss model. And converting the temperature response in the frequency domain into periodic steady-state temperature fluctuation distribution in the time domain.