comsol-multiphysics

name comsol-multiphysics description Set up coupled fluid-structure interaction for pump vibration analysis category integrations domain multiphysics complexity advanced dependencies [] COMSOL Multiphysics Integration Comprehensive guide for setting up and automating coupled fluid-structure interaction (FSI) simulations using COMSOL Multiphysics, with a focus on pump vibration analysis and related multiphysics applications. Overview COMSOL Multiphysics is a leading commercial simulation platform for modeling and solving complex multiphysics problems. It provides: Unified Environment : Single platform for multiple physics domains Flexible Coupling : Built-in tools for coupling different physics Equation-Based Modeling : Direct access to underlying PDEs Java API : Programmatic control and automation MATLAB LiveLink : Integration with MATLAB for pre/post-processing Application Builder : Create custom simulation apps COMSOL excels at coupled physics problems including: Fluid-structure interaction (FSI) Thermal-structural coupling Electromagnetics with thermal effects Acoustics-structure interaction Electrochemistry with transport phenomena COMSOL Architecture Model Structure Component : Independent geometry and physics Study : Solution sequence with one or more steps Physics Interfaces : Pre-configured PDE systems for specific phenomena Multiphysics Couplings : Automatic or manual coupling between physics Solver Configurations : Automatic or customized solver sequences Solver Technology COMSOL Solver : Direct and iterative solvers Fully Coupled Approach : Simultaneous solution of all equations Segregated Solver : Physics-based segregation for large models Time-Stepping : Implicit methods for transient analysis Mesh Adaptation : Automatic refinement based on solution Licensing Requirements Commercial Licensing COMSOL Multiphysics requires commercial licenses for all production use: Base Package : COMSOL Multiphysics license (required for all users) Includes basic PDE interfaces and computational tools License managed via FlexNet License Server Module Licenses : Individual modules purchased separately Floating licenses (checked out during use) Batch mode requires license checkout HPC add-ons for parallel computing License Server Setup : # Set license server environment variable (Linux/Mac) export LMCOMSOL_LICENSE_FILE=1718@license-server.company.com # Or in Windows set LMCOMSOL_LICENSE_FILE=1718@license-server.company.com License Types : Floating Network License : Shared among users Node-Locked License : Tied to specific machine HPC License : Additional cores for parallel computing Batch License : For batch/automated simulations Academic Licensing Classroom Kit: Limited to educational use Research licenses: Available for academic institutions Restrictions on commercial applications May have feature or model size limitations Important Licensing Notes License Check : Always verify license availability before batch runs License Release : Properly close COMSOL to release licenses Batch Operations : Require special batch/HPC licenses Module Dependencies : Some modules require others (e.g., FSI needs CFD + Structural) API Access : Requires base license plus relevant modules Key Modules for Pump Applications CFD Module Comprehensive computational fluid dynamics for single-phase and multiphase flows: Capabilities: Turbulence Models : RANS: k-epsilon, k-omega, SST LES and DES for high-fidelity simulations Wall functions and low-Re formulations Flow Types : Incompressible and compressible Laminar and turbulent Steady-state and transient Rotating machinery (frozen rotor, sliding mesh) Multiphase Flow : Euler-Euler multiphase Phase field methods Level set tracking Bubbly flow models Pump-Specific Features: Rotating reference frames for impellers Mixing plane interfaces Cavitation modeling Pressure pulsation analysis Structural Mechanics Module Comprehensive structural analysis including linear and nonlinear behavior: Capabilities: Analysis Types : Static structural analysis Eigenfrequency analysis (modal analysis) Frequency response analysis Transient dynamics Prestressed analysis Material Models : Linear elastic Hyperelastic (rubber, polymers) Plasticity (metals under high stress) Composite materials Contact and friction Dynamic Analysis : Modal analysis for natural frequencies Harmonic response Time-dependent loading Damping models (Rayleigh, modal) Pump-Specific Features: Rotating machinery stress analysis Bolt preload and assembly stress Fatigue analysis Contact between impeller and casing Fluid-Structure Interaction (FSI) Couples CFD and Structural Mechanics for two-way interaction: Coupling Approaches: One-Way FSI : Fluid loads applied to structure Structure does not affect fluid Faster computation Suitable for rigid-like structures Two-Way FSI : Fully coupled fluid and structure Deforming mesh methods Accounts for large deformations Required for flexible structures Weak Coupling : Sequential solution (staggered approach) Fluid → Structure → Fluid iteration Better for loosely coupled problems Strong Coupling : Fully implicit simultaneous solution Better convergence for tightly coupled problems Higher computational cost FSI Features: Automatic mesh deformation (ALE method) Remeshing for large deformations Fluid loads computed automatically Pressure and viscous forces transferred Support for multiple solid bodies Pump FSI Applications: Impeller blade vibration under fluid forces Casing vibration and acoustic radiation Seal deflection under pressure Shaft deflection and critical speeds Cavitation-induced vibration Additional Relevant Modules Acoustics Module: Pressure pulsation analysis Noise radiation from pump casing Structure-borne noise Coupled acoustic-structure-fluid problems Heat Transfer Module: Thermal loads in pumps Coupled thermal-structural analysis Conjugate heat transfer (fluid-solid) Thermal expansion effects Optimization Module: Design optimization Topology optimization Shape optimization Parameter sweeps Java API for Automation COMSOL provides a comprehensive Java API for programmatic model building and automation: API Structure Core Components: Model object : Top-level container Component : Geometry and physics Physics interfaces : Add and configure physics Study : Define solution procedures Results : Post-processing and visualization Basic Java API Workflow import com.comsol.model.*; import com.comsol.model.util.*; public class PumpFSI { public static Model run () { // Create model Model model = ModelUtil.create( "PumpFSI" ); // Create component model.component().create( "comp1" , true ); // Create geometry model.component( "comp1" ).geom().create( "geom1" , 3 ); // Import CAD geometry model.component( "comp1" ).geom( "geom1" ).create( "imp1" , "Import" ); model.component( "comp1" ).geom( "geom1" ).feature( "imp1" ) .set( "filename" , "/path/to/pump_geometry.step" ); model.component( "comp1" ).geom( "geom1" ).run(); // Add fluid physics (CFD) model.component( "comp1" ).physics().create( "spf" , "LaminarFlow" , "geom1" ); model.component( "comp1" ).physics( "spf" ).selection() .named( "geom1_fluid_domain" ); // Add structural physics model.component( "comp1" ).physics().create( "solid" , "SolidMechanics" , "geom1" ); model.component( "comp1" ).physics( "solid" ).selection() .named( "geom1_solid_domain" ); // Add FSI coupling model.component( "comp1" ).multiphysics().create( "fsi1" , "FluidStructureInteraction" , 3 ); model.component( "comp1" ).multiphysics( "fsi1" ) .selection().named( "geom1_fsi_boundary" ); // Create mesh model.component( "comp1" ).mesh().create( "mesh1" ); model.component( "comp1" ).mesh( "mesh1" ).automatic( true ); model.component( "comp1" ).mesh( "mesh1" ).run(); // Create study model.study().create( "std1" ); model.study( "std1" ).create( "time" , "Transient" ); model.study( "std1" ).feature( "time" ).set( "tlist" , "range(0,0.01,1)" ); // Solve model.sol().create( "sol1" ); model.sol( "sol1" ).study( "std1" ); model.sol( "sol1" ).feature().create( "st1" , "StudyStep" ); model.sol( "sol1" ).feature().create( "v1" , "Variables" ); model.sol( "sol1" ).feature().create( "t1" , "Time" ); model.sol( "sol1" ).attach( "std1" ); model.sol( "sol1" ).runAll(); // Save model model.save( "/path/to/pump_fsi_model.mph" ); return model; } public static void main (String[] args) { run(); } } Running Java API Scripts # Compile Java file comsol compile PumpFSI.java # Run with COMSOL comsol batch -inputfile PumpFSI.class -outputfile results.mph # Or run directly java - cp /path/to/comsol/plugins/*:. PumpFSI API Advantages Reproducibility : Scripts ensure consistent model building Parametric Studies : Easy to vary parameters Batch Processing : Run multiple cases automatically Integration : Connect with other tools and databases Version Control : Track model changes in source control MATLAB LiveLink COMSOL integrates seamlessly with MATLAB for enhanced scripting and data processing: LiveLink Features Model Control from MATLAB: Build and modify COMSOL models Run simulations from MATLAB scripts Extract results into MATLAB workspace Use MATLAB's data analysis tools Installation: Requires separate LiveLink for MATLAB license Configure MATLAB path to COMSOL installation Start COMSOL server or use direct connection Basic MATLAB LiveLink Usage % Initialize COMSOL with MATLAB import com.comsol.model.* import com.comsol.model.util.* % Start COMSOL server (if not already running) mphstart % Create or load model model = mphload('pump_model.mph'); % Modify parameters model.param.set('inlet_velocity', '5[m/s]'); model.param.set('outlet_pressure', '101325[Pa]'); % Run study model.study('std1').run(); % Extract results pressure = mpheval(model, 'p', 'dataset', 'dset1'); velocity = mpheval(model, 'u', 'dataset', 'dset1'); % Process in MATLAB mean_pressure = mean(pressure.d1); max_velocity = max(sqrt(velocity.d1.^2 + velocity.d2.^2 + velocity.d3.^2)); % Plot using MATLAB figure; plot(pressure.p, pressure.d1); xlabel('Position'); ylabel('Pressure [Pa]'); title('Pressure Distribution'); % Save results save('pump_results.mat', 'pressure', 'velocity'); % Close COMSOL ModelUtil.remove('model'); Parametric Study with MATLAB % Parametric study of inlet velocity effects velocities = 1:1:10; % m/s results = struct(); for i = 1:length(velocities) fprintf('Running case %d: velocity = %.1f m/s\n', i, velocities(i)); % Set parameter model.param.set('inlet_velocity', sprintf('%f[m/s]', velocities(i))); % Solve model.study('std1').run(); % Extract force on impeller force = mphint2(model, 'spf.Fp_x', 'surface', 'selection', 5); results(i).velocity = velocities(i); results(i).force = force; % Extract vibration amplitude displacement = mphmax(model, 'sqrt(u^2+v^2+w^2)', 'volume', 'selection', 3); results(i).max_displacement = displacement; end % Plot results figure; subplot(2,1,1); plot([results.velocity], [results.force], '-o'); xlabel('Inlet Velocity [m/s]'); ylabel('Force on Impeller [N]'); grid on; subplot(2,1,2); plot([results.velocity], [results.max_displacement]*1e6, '-o'); xlabel('Inlet Velocity [m/s]'); ylabel('Max Displacement [μm]'); grid on; % Save results save('parametric_results.mat', 'results'); Common Workflows Workflow 1: Pump Casing Vibration Under Fluid Loads Application : Analyze vibration of pump casing due to pressure pulsations from fluid flow. Approach : One-way FSI (fluid loads mapped to structure) Steps: Geometry Setup : Import pump casing geometry Create fluid domain inside casing Define FSI boundary (fluid-structure interface) CFD Setup : Define inlet and outlet boundaries Set up turbulence model (k-epsilon or k-omega SST) Configure transient solver Apply rotating reference frame if analyzing flow with rotating impeller Structural Setup : Define material properties (steel, cast iron) Apply boundary conditions (fixed support at mounting points) Set up transient structural analysis Include damping if known FSI Coupling :