Example from mecanics of the fluids

Sunday, March 05, 2006


Law on the flows

When one measures the speed to which a basin is emptied, one measures a
variation of level of the basin. The reference mark is the bottom of
the basin with like locates algebraic the zero. This water which is not
any more in the basin left in a place located low only the algebraic
value. Initially this water always exists, and is some share on a total
reference mark. Thus the bottom of the basin is a balance and the
formula of the flow will be the height starting factor of expo of less
time on OJ which depends on the form of the evacuation and which
varies. One should not lose sight of the fact that the final result is
a balance of a value which should not in no case to be comparable to

Analyze of a step

Formulate and analyzes particular case of the swirls.

Drawn from the observation of the lock of Nourriguier, the swirls are
transformed into solitary wave when they do not have enough place for
dévelloper. This wave goes up the current.

There is a high limit and a low limit in the appearance of a swirl.
These limits depend the total head and on the flow.

Cavitation (liquid/gas) can generate swirls which will go in the
direction of the current. Always with the same law of the limits

Experimental data measured on a flow of water:

initial time of 0,01s since the zero are not defined, the height is 60
cm from where:

H = 60; T = 0,01 S

H = 55; T = 13,33 S

H = 50; T = 16,58 S

H = 45; T = 21,14 S

H = 40; T = 27,08 S

H = 35; T = 34,44 S

H = 30; T = 42,27 S

H = 25; T = 49,94 S

H = 20; T = 59,32 S

H = 15; T = 77,13 S

H = 10; T = 119,27 S

If one take the current formula simplified for reasons of concept (What
is in addition advised by the books of analysis); the flow is equal to
a constant, factor of the square root of the difference in pressure.

Always for reasons of concept I thus release myself from the problems
of dimension to thus compare only the function square root of the
pressure height by a factor K (the exit being with a negligible

If one takes the values referred to above and that one calculates the
medium flow, one realizes that qelles that are dimensions of volume and
property of flow which one applies to measurement there is a shift of
factor four which pushes me to seek a new formula. It is true that the
current formula gives an aspect resembling the real curve
éffectuée by a flow, but in the application of my trade,
I refined another proposal for a formula.In the final analysis the
formula that I propose is an alternative of a naturally stable system.
An alternative because it appears a constant. The result obtained being
the level of water, there is the function of the flow in the function
of the variation, these functions being naturally stable.

Moreover if I vary the drain opening thus the flow, I can obtain a
particular case which will correspond to the formula K factor of the
square root the height if not the formula is the height of origin
factor of expo of less time that OJ divides. This value OJ being it
even a built variable of constant a factor of

author: Andre pierre jocelyn

Hypothesis on time