回転翼による噴流の作用について (第1報)

噴流内の風速分布

抄録

To know about the velocity distribution of wind from a fan, this study was done firstly about the relation between the various forms of wing and the wind velocities at near points from the wings, and about the expression of the distribution of wind velocity jetting from the nozzle which is assumed as a point. In this case, the distributions of the wind velocity are expressed in the following form,
U=KU_oz^-1exp{-2√2/3ck(r/z)^3/2}
where r is the radial distance from the center axis of jet flow,
z is the distance from the original point along the center axis,
c and k are the coefficients of the diffusion of a jet flow and the mixing length respectively,
K is constant.
Then applicating it to the jet flow from the limited wing radius on which initial wind velocity was led, the wind velocities in any place are decided as a sum of the following three velocities.
U₁=∫^P_QKz^-1f(n)exp{-2√2/3ch(n-r/z)^3/2}dn
U₂=∫^Q_RKz^-1f(n)exp{-2√2/3ck(r-n/z)^3/2}dn
U₃=∫^S_HKz^-1f(n)exp{-2√2/3ck(r+n/z)^3/2}dn
U=U₁+U₂+U₃
where n is the auxiliary variable of r and f(n) is a function of the initial wind velocity.
The integrating ranges are decided according with the length of wing and the radius of center boss.
This expression was correspondent to the experimental data through a home fan counting c=0.22 and K=0.16, but these coefficients must be consulted by many practical uses of Helicopter and Speed Sprayer etc.