code: def headloss_kozeny(Length, Diam, Vel, Porosity, Nu):
      
      #Checking input validity
      ut.check_range([Length, ">0", "Length"], [Diam, ">0", "Diam"],
                     [Vel, ">0", "Velocity"], [Nu, ">0", "Nu"],
                     [Porosity, "0-1", "Porosity"])
      return (K_KOZENY * Length * Nu
              / gravity.magnitude * (1-Porosity)**2
              / Porosity**3 * 36 * Vel
              / Diam ** 2)
docs: Return the Carmen Kozeny Sand Bed head loss.