Contents
Generate physical parameters for the fluid-particle simulations
Generate a set of default parameters or used parameters from a CVS file.
Units: [time]=ms, [length]=microns, [mass]=mg.
- Boltzman constant times temperature: microns^2*mg/ms^2
- Solvent density: water mg/microns^3
- Solvent dynamic viscosity: water mg/microns/time
- Particle's radius: microns
- G0: mean polymer stress (fixed)
- Smallest relaxation time: ms
- Time step, number of time steps, number of paths
- Length of the domain: microns
- Number of Fourier modes
- Maximum simulation time
- Relaxation times: given as Generalized Rouse spectrum
- Average relaxation time
- Polymer dynamic viscosity: given as the mean polymer stress divided by the average relaxation time
- Solvent and polymer kinematic viscosity
Non dimensional groups:
: characteristic time
: nondimensional parameter for particle
: nondimensional parameter for fluid- U: characteristic velocity
- Reynolds number
- Necessary nondimensional times and lengths
Christel Hohenegger
Last updated: 05/16/2016
function parameters = GenParameters(paramMat)
Dimensional variables
parameters.kbt = 4.1e-9; parameters.rho = 1e-9; switch nargin case 0 parameters.etasol = 1e-6; parameters.radius = 1; parameters.numKernels = 1e0; parameters.G0 = 1e-4; parameters.tau0 = 1; parameters.dt = 1; parameters.numTsteps = 2^5; parameters.numPaths = 1e3; parameters.length = 10; parameters.numFmodes = 4; parameters.tFinal = parameters.numTsteps*parameters.dt; otherwise parameters.etasol = paramMat(1); parameters.radius = paramMat(6); parameters.numKernels = paramMat(8); parameters.G0 = paramMat(2); parameters.dt = paramMat(10); parameters.tFinal = paramMat(5); parameters.numPaths = paramMat(7); parameters.length = paramMat(3); parameters.numFmodes = paramMat(9); parameters.tau0 = paramMat(4); end parameters.tau = parameters.tau0*(parameters.numKernels... ./(parameters.numKernels-(0:parameters.numKernels-1))).^(2); parameters.tauavg = 1/parameters.numKernels*sum(parameters.tau); parameters.etapol = parameters.G0*parameters.tauavg; parameters.nusol = parameters.etasol/parameters.rho; parameters.nupol = parameters.etapol/parameters.rho;
ND groups and variables
parameters.theta = parameters.length^2/parameters.nusol;
parameters.tauND = parameters.tau/parameters.theta;
parameters.tauavgND = parameters.tauavg/parameters.theta;
parameters.dtND = parameters.dt/parameters.theta;
parameters.numTsteps = parameters.tFinal./parameters.dt;
parameters.kappa = sqrt(parameters.kbt*parameters.rho)/parameters.etasol;
parameters.beta = parameters.nupol*parameters.length^2 ...
/(parameters.nusol^2*parameters.tauavg);
parameters.U = sqrt(parameters.kbt/parameters.rho/parameters.length^3);
parameters.lengthND = parameters.length/parameters.length;
parameters.radiusND = parameters.radius/parameters.length;
parameters.Reynolds = parameters.U*parameters.length/parameters.nusol;