Comsol 5.3 discretization of fluids full#

For media of higher complexity, for example, in a packed bed of solids, where is the mean grain diameter, is the porosity, and is a parameter that is dependent on cross-sectional geometry. For tubes of elliptical cross sections,, where and are the semiaxes similar results are available for several other shapes. For example, in a straight tube of circle-shaped cross sections, one obtains by combining three equations: (Hagen-Poiseuille law), (DarcyР Р†Р вЂљРІвЂћСћs law), and (relation between permeability and conductivity) (see, e.g., ). Some studies have been devoted to establishing the relationship between microscopic geometry and macroscopic permeability by theoretical models and numerical calculations, which are becoming increasingly valuable for the growing availability of microscopic tomographic data, such as nuclear magnetic resonance, X-ray microtomography, and scanning-electron-microscopic imaging ( among many others).Р вЂќР вЂЎor pores of some of the simplest geometries, the permeability can be calculated by the exact solution to the Poiseuille flow equation. In addition to the direct measurement of samples, indirect measurement is also important for different environmental and technological applications. Р вЂќР вЂћs a macroscopic parameter of formations, permeability is closely related to pore microstructures. Since permeability (or hydraulic conductivity) greatly influences the fluid movements and flow fields of groundwater, it is generally the fundamental factor in all groundwater-related problems, such as groundwater exploitation, surface-groundwater interaction, contaminant transport, agricultural irrigation, and site selection for radioactive waste disposal. Permeability, which is a measure of the ability of a porous material to allow fluid to pass through it, is one of the most important properties of geologic formations to hydrogeologists, petrophysicists, and other geologic fluid researchers. In a synthetic complex pore, the permeability estimated by WOG is comparable to, but greater than, the estimate based on the pore-scale dynamics simulation in COMSOL. The results suggested that MPDs based on GreenР Р†Р вЂљРІвЂћСћs functions and WOG are consistent with each other the factor in the permeability expression is slightly dependent on roundness of the cross sections and is approximately 1.125 on average, according to analytical and numerical results. Moreover, the accurate MPDs for the pores of simple shapes are derived with GreenР Р†Р вЂљРІвЂћСћs functions to validate the WOG-based MPD. In this study, an MPD method that is based on a more flexible Р Р†Р вЂљРЎС™random walk on gridР Р†Р вЂљРЎСљ (WOG) is explored. However, these two methods encounter difficulties such as irregular boundaries and the determination of arrivals at a boundary.

You can use moving frames to solve a problem where a structure slides in relation to another structure with fluid flow in between, which is easy to set up and solve by employing a moving mesh.In the literature, the mean penetration depth (MPD) calculated by Р Р†Р вЂљРЎС™walk on spheresР Р†Р вЂљРЎСљ or Р Р†Р вЂљРЎС™walk on cubesР Р†Р вЂљРЎСљ was used to quickly estimate the intrinsic permeability of digitized porous media. Generally speaking, the CFD Module can also solve fluid flow problems on any moving frame, not just on rotating frames, for example opening and closing valves. The frozen rotor approach is computationally inexpensive and can be used to estimate averaged velocities, pressure changes, mixing levels, averaged temperature and concentration distributions, and more.

Comsol 5.3 discretization of fluids full#

You can solve problems using either a full time-dependent description of the rotating system or an averaged approach based on the frozen rotor approximation. The CFD Module provides rotating machinery interfaces that formulate the fluid flow equations in rotating frames, available for both laminar and turbulent flow. Rotating machines, such as mixers and pumps, are common in processes and equipment where fluid flow occurs. The simulation environment looks the same regardless of what you are modeling. Additional multiphysics couplings can be added together with other modules from the COMSOL product suite, such as combining fluid flow with large structural deformations in FSI.

The CFD Module provides you with the tools to model nonisothermal flow with conjugate heat transfer, reacting flow, fluidР Р†Р вЂљРІР‚Сљstructure interaction (FSI), and electrohydrodynamics (EHD). The multiphysics capabilities are virtually unlimited within the module and in combination with other add-on modules to COMSOLР вЂ™Р’В Multiphysics Р вЂ™Р’В®. The CFD Module provides tools for modeling the cornerstones of fluid flow analyses, including: Perform computational fluid dynamic simulations with the CFD Module, an add-on product to the COMSOLР вЂ™Р’В Multiphysics Р вЂ™Р’В® software. Simulate Single-Phase and Multiphase Flow