Procedure for predicting and designing moving sprinkler application patterns |
| |
| Authors: | I Amir V Alchanatis |
| |
| Institution: | (1) Department of Agricultural Engineering, Technion, Israel Institute of Technology, 32000 Haifa, Israel |
| |
| Abstract: | Summary Water application pattern, WAP, is one of the most important factors that determine the instantaneous and the cumulative application rates of moving irrigation machines. The mathematical background of a procedure to predict and design the WAP of moving irrigation machines is introduced. It includes a mathematical analysis of the effect of pressure head, height and spacing between emitters on the WAP, and a nomograph that presents this analysis graphically and illustrates the design procedure of the application pattern of irrigation machines.Abbreviations
P( )a
water application rate at a normalized radial distance from the emitter m/s]
-
ka
number of linear segments needed to represent the pattern
-  s/Ra
normalized radial distance from the emitter
-
Ra
wetted radius m]
-
sa
radial distance from the emitter m]
-
n
j n
i/ha
normalized water application rate at point
-
j, ha
maximum water application rate m/s] n
j water application rate at point j m/s]
- 
j
=m
j/Ra
normalized radial distance of point j from emitter
-
m
ja
radial distance of point
-
ja
from emitter m], CWAP
- (x)a
Cumulative Water Application Pattern: amount of water per unit area applied at a distance
-
xa
from the travel path of the emitter m3/m2]
-
xa
distance from the travel path of the emitter m]
-
T
xa
time of application at a distance
-
xa
from the travel path of the emitter s]
-
va
velocity of propagation of the machine m/s]
-
k
1a
the outmost linear segment that its radial distance from the emitter
-
m
k1a
is smaller than the distance of the travel path from the emitter
-
x, T
ja
time at which the
-
j
tha
linear segment (ring) stops influencing the point located at a distance
-
xa
from the emitter
-
1,
2,
3a
dimensionless numbers derived by dimensional analysis
-
ua
water jet velocity m/s]
-
ga
gravity acceleration m/s2]
-
da
nozzle diameter m], v kinematic viscosity m2/s]
-
Ha
emitters height m]
-
 ,  a
regression analysis coefficients
-
Paa
Pattern fit coefficient for water application
-
F(r)a
normalized desired water application pattern 1/m]
-
f(r)a
normalized actual water application pattern 1/m]
-
La
common distance on which
-
F(r) and f(r)a
are defined m], SP spacing interval between emitters m]
-
DSa
dimensionless spacing interval between emitters
-
 DSa
variation of dimensionless spacing interval
-
Paa
variation of Pa coefficient
-
Pa
pressure head kPa] |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
