46 results about "Mesh adaptation" patented technology

The invention discloses a CFD simulation and grid self-adaption based valve flow coefficient calculating method. The CFD simulation and grid self-adaption based valve flow coefficient calculating method comprises the main steps that a 'valve-pipe' flow field model and a 'straight pipeline' flow field model are extracted based on a valve assembly body three-dimensional model; initial grids are divided for the flow field models, wherein multiple groups of initial grids different in scale are divided for the 'valve-pipe' flow field model; trial operation is performed by applying the groups of initial grids respectively, the change tends with grid scales of the obtained pressure differences are compared to select optimal initial grids; the optimal initial grids are applied to set different boundary conditions, and simulating calculation of corresponding flow coefficients is performed by combining a grid self-adaption technology; finally, the arithmetic average of the obtained flow coefficients is obtained to serve as a valve flow coefficient prediction result. The CFD simulation and grid self-adaption based valve flow coefficient calculating method can more rapidly and flexibly predict the flow capacity of a valve under various conditions, shorten a development period and improve the design quality and can effectively improve the calculation accuracy and reduce the dependence on specialization level of operators.

The invention discloses a BESO topological optimization method based on a dynamic evolution rate and an adaptive grid and application thereof, and the method comprises the steps: building a finite element model for a to-be-topologically optimized basic structure, and defining a design domain, a load, a boundary condition and a grid size; determining a constraint value and BESO necessary parameters; performing finite element analysis on the structure after mesh division, and calculating unit sensitivity under a target function and a constraint condition; filtering the unit sensitivity and updating the constrained Lagrange multiplier, and constructing the sensitivity of a Lagrange function; determining an evolution rate of the current iterative step based on a dynamic evolution rate functionof a Logistic function according to the volume rate of the current iterative step; and updating a design variable according to a set constraint function, judging whether constraint conditions and convergence conditions are met or not, if not, performing grid adaptive updating, then performing unit updating, and stopping iteration until the constraint conditions and the convergence conditions aremet. According to the invention, the calculation amount of single finite element analysis and the number of iterations required by topological optimization are effectively reduced while high calculation precision is ensured, so that the total calculation time consumption of topological optimization is greatly reduced.

The invention discloses a numerical simulation test method for impacting a flat solid surface by double liquid drops based on VOF and dynamic grid self-adaptation. The method comprises the steps thatfirstly, an ideal computational domain size is defined in gerris software, and boundary conditions of a computational domain are determined; secondly, importing a solid boundary and defining a solid boundary condition; secondly, assigning an initial condition, and giving an initialization grid; furthermore, a Cartesian grid dynamic self-adaptive refining function is used; then, resolving the wholecalculation domain, and outputting a corresponding calculation result; and finally, importing the output calculation result into the simulation result of the visualized gerris in the text. Accordingto the method, the numerical simulation method for impacting the flat solid surface by the double liquid drops based on VOF and dynamic grid self-adaptation is achieved, the flowing process of impacting the flat solid surface by the double liquid drops is obtained, and an accurate numerical calculation method is provided for analyzing the flowing rule and flow state characteristics of the flat solid surface by the double liquid drops.

The invention discloses a self-adaptive grid disturbance domain updating acceleration method for aircraft aerodynamic characteristic prediction, which comprises the following steps of: firstly, providing a novel data format for coupling storage of a self-adaptive grid and a dynamic computational domain so as to realize efficient storage and traversal of dynamic computational domain information on the self-adaptive grid; secondly, establishing a self-adaptive detector capable of identifying characteristic units which are positioned in a detached strong shock wave region and are slow in convergence and the like; thirdly, establishing a self-adaptive strategy of the anisotropic encrypted grid in the decoupled strong shock wave region, which can accelerate convergence and can minimize calculation increment; and finally, establishing coupling logic of adaptive grid encryption and dynamic computational domain updating and an algorithm thereof, and proposing a self-adaptive grid disturbance domain updating acceleration method. According to the method, the acceleration effect of an existing disturbance domain updating method can be further improved; compared with a traditional global updating method, the method can provide a technical approach for optimizing the grid and the computational domain at the same time for aerodynamic characteristic prediction of the aircraft.

The embodiment of the invention discloses a right-angle grid self-adaptive modeling method suitable for a grid Boltzmann method. The modeling method comprises the following steps: S101, dividing a root grid unit into right-angle sub-grid units to obtain an initial grid comprising an initial object plane grid and an initial flow field grid; S102, performing right-angle grid self-adaptive processingon the initial object plane grid to obtain a final self-adaptive object plane grid, and taking the final self-adaptive object plane grid and the initial flow field grid as an initial calculation grid; S103, solving the flow field by adopting a lattice Boltzmann method based on the current calculation grid to obtain a current flow field calculation result, and obtaining a flow field calculation adaptive parameter based on the current flow field calculation result; S104, judging whether all flow field calculation self-adaptive parameters are smaller than a first set threshold value or not; S105, if so, taking the current flow field calculation result as a final flow field calculation result, and if not, carrying out right-angle grid adaptive processing on the current flow field grid, takingthe current flow field grid and the final adaptive object plane grid as a new calculation grid, and returning to the step S103.

The invention discloses a gas explosion simulation method based on a self-adaptive simplified reaction and mesh subdivision. The gas explosion simulation method is characterized by comprising the steps that explosive gas component attributes are determined; chemical reaction kinetics analysis is conducted on explosive gas, and an explosive gas detailed reaction mechanism; a phase parameter threshold set in an explosion field generated through explosion is determined by adopting the detailed reaction mechanism obtained through a self-adaptive simplified reaction method; self-adaptive mesh subdivision is conducted on areas high in pressure and density gradient in the explosion field, and shock waves in the explosion field and time-space evolution of shock wave temperature, pressure and component concentration are captured. According to the method, the problem that gas explosion safety large-scale simulation is low in computing efficiency in real explosion accident site calculation can be solved.

An image segmentation method segments a plurality of image features in an image. The plurality of image features are segmented non-simultaneously in succession. The segmenting of each image feature includes adapting an initial mesh to boundaries of the image feature. The segmenting of each image feature further includes preventing the adapted mesh from overlapping any previously adapted mesh.

This invention relates to one visual network self-adaptive load even transfer method in computer multi-media field, which comprises the following steps: generating dynamic area corporation member list, service point virtual organization point list and belong service point provider list; after customer sends requires, network grid door automatically set its direction to service points and judging whether the real servo satisfies the service quality requires; if yes, ending this transfer; if not, according to dynamic area load value to judge whether the service point satisfies the service needs.

The invention discloses a gas explosion simulation method based on a self-adaptive simplified reaction and mesh subdivision. The gas explosion simulation method is characterized by comprising the steps that explosive gas component attributes are determined; chemical reaction kinetics analysis is conducted on explosive gas, and an explosive gas detailed reaction mechanism; a phase parameter threshold set in an explosion field generated through explosion is determined by adopting the detailed reaction mechanism obtained through a self-adaptive simplified reaction method; self-adaptive mesh subdivision is conducted on areas high in pressure and density gradient in the explosion field, and shock waves in the explosion field and time-space evolution of shock wave temperature, pressure and component concentration are captured. According to the method, the problem that gas explosion safety large-scale simulation is low in computing efficiency in real explosion accident site calculation can be solved.

The invention relates to a method for self-adaptive correction of model grids under the condition of extreme compression and deformation. coordinates; calculate the updated coordinate position of the node correction; find the code of the grid unit where the node will fall, and perform linear interpolation on the displacement field of the node in the x and z directions according to the positions of the four nodes that make up the grid unit, and get The new coordinates of the nodes; traverse the grid units, and find the corresponding grid unit codes according to the new coordinates, and at the same time obtain the center coordinates of the grid units, linearly interpolate the stress and strain of the units where the new coordinates of all nodes are located, and obtain the strain information, and store the stress and strain information into the extra variables of the unit; re-traverse the nodes, and update the node coordinate position and node displacement information; re-traverse the grid unit, and update the unit stress and strain information.

The invention discloses a near-field dynamic modeling method for a composite mass diffusion problem. The method comprises the following steps of 1, building an entity model; 2, cutting the entity model, determining layering and mixing region positions of materials in the model, and giving corresponding material attributes to the regions; 3, dividing the entity model into unit grids; 4, setting concentration boundary conditions of the entity model; 5, on the basis of mass diffusion near-field dynamic constitutive relation, integrating model parameters, determining a calculation method for concentration changes of a diffusing substance in a composite in the entity model, and calculating operation parameters of all units in the entity model; 6, performing submission calculation. The modelingmethod is high in precision and good in grid adaptability, all the parameters in the model are preprocessed, the operation complexity can be greatly lowered, and an algorithm is greatly optimized; themodeling method and the operation process are large in adaptability and applicable to many problems.