[Kozan]

Hello!

I'm quite new in OpenFoam and Python, therefore I have decided to write short script for the turbulence kinetic energy and dissipation rate computation.Code of the sripts follows:

def VypocetTurbVelicin(velocity, hydraulic_diameter, mu):
reynolds = (velocity * hydraulic_diameter)/mu
cmu = 0.09
intensity = 0.05
fluct_velocity = intensity * velocity
global k
k = 3/2 * ((fluct_velocity)**2)
turbulence_lengthScale = 0.038 * hydraulic_diameter
global epsilon
epsilon = (cmu * k**(3/2))/turbulence_lengthScale
return k, epsilon

k = None
velocity = float(raw_input("Velocity: "))
hydraulic_diameter = float(raw_input("Hydraulic diamter: "))
mu = float(raw_input("Kinematic viscosity : "))

VypocetTurbVelicin(velocity, hydraulic_diameter, mu)
print "turbulence kinetic energy: " + str(k)
print "turbulence dissipation rate: " + str(epsilon)

Problem is that the results of my script are different compared to the calculator which is available on the cfd-online (http://www.cfd-online.com/Tools/turbulence.php)

I can't find the problem. Thank you very much for any advice

For example results for
vel = 4.2 m.s^(-1)
visc = 1E-6 m^(2).s^(-1)
hydraulic diameter = 0.3 m
turbulence intensity = 5%

are:
My script:

k = 0.0441
eps = 0.348157894737

CFD online calculator
(Turbulence variables (k, ε, ω) from turbulence intensity (Tu), length-scale (TuL) and freestream velocity (U∞)):

k = 0.06615000000000001
eps = 0.13431744774423365