1. Hydraulic radius
A Wetted Area [m2]
R 
P Wetted Perimeter [m]
R = Hydraulic Radius [m] R = Hydraulische straal [m]
A = Wetted Area [m2] A = Natte oppervlakte [m2]
P = Wetted Perimeter [m] P = Natte omtrek [m]
2

2. Reynolds number
𝜇= Absolute viscosity [m2/s] 𝑉. 4𝑅
𝜐= Kinematic viscosity [kg/ms] 𝑅𝑒 =
water, 20°C= 1,00 ∙ 10−6 𝜈
𝜌 = Density of liquid [kg/m3]
𝑉 = Velocity [m/s]
D = Hydraulic diameter [m]
R= Hydraulic Radius = D/4 [m]
𝑅𝑒 = Reynolds Number [1]
𝑹𝒆 > 𝟒𝟎𝟎𝟎 Turbulent flow
𝑹𝒆 < 𝟐𝟎𝟎𝟎 Laminar flow
5