In order to simulate the flow-field in multirow turbomachines

a model equation

named Time-averaged Effect Navier-Stokes equation

(hereafter referred to as TENS equation)has been firstly deduced.This TENS equation was obtained from ensemble average and time average processes in succession.As distinguished from Renolds-averaged N-S equation

the TENS equation has time-averaged stresses and time-averaged energy source terms to consider the zero order unsteady effect.As a result

it gives a better engineering method to transmit parameters across the interface of neighbour blade rows.