Page 396 - Handbook of Energy Engineering Calculations

FIGURE 4 Level changes during power production in a single-pool
tidal system.

where H = ocean level above mean or other appropriate datum
y = pool level above mean or datum
θ = time

and the other symbols have already been defined. H may be closely
approximated by a sinusoidal function of θ such as

where θ is in hours and 6.2083 in hours is one-half of a tidal period, y may be
approximated by a linear function of θ, starting at 0 at θ for a constant mass-
1
flow rate such as
y = f (θ) = aR(θ–θ )
1
2
–1
−1
where a is a constant having the dimension time , e.g., h , or y could be a
function of h = H − y for a constant flow resistance or some other function
determined from operational data.

W = work done by the water, ft · lb or J
f
2
g = gravitational acceleration, 32.2 ft/s or 9.81 m/s 2
2
2
g = conversion factor, 32.2 lb · ft/(lb · s ) or 1.0 kg/(N · s )
c
f
m
m = mass flowing through turbine, lb or kg
m
h = head, ft or m
3
ρ = water density, lb /ft or kg/m 3
m
2
A = surface area of pool, considered constant, ft or m 2

Then,