% coeff = CalcCoeff(oscfit) % % Helper function for AnalyzeCoordinates. % Calculates the oscillation coefficients of a ferrofluid droplet % in magnetic field based on fitted harmonic oscillator model. % % oscfit = fit to oscillation data (t (ms), x (mm)) % % coeff = Structure containing the oscillation coefficients: % .k = Magnetic spring constant % .Fmu = CAH-force % .beta = Viscous damping coefficient function coeff = CalcCoeff(oscfit) m = 1.0069e-05; % Mass of the 10 mul ferrofluid droplet (kg). T = oscfit.T/1000; % Oscillation period in seconds. a_0 = oscfit.a_0/1000; % Max peak amplitude in meters. % You don't have to worry about the following formulas. However, if you % really want to, there is an article called "Motion of a harmonic % oscillator with sliding and viscous friction". You can ask the assistant % about it. % Magnetic spring constant k: coeff.k=4*m/(T*T)*(pi*pi+oscfit.g*oscfit.g); % CAH-force Fmu: coeff.Fmu=coeff.k*a_0*oscfit.a; % Viscous damping coefficient beta: coeff.beta = 2*m*oscfit.g/T;