View source for Information about the Lateral Profile Applet

Author: [mailto:info.hamburg@baw.de A. Malcherek]

==General Description==
The Lateral Profile Applet (LPA) calculates the lateral velocity profile in a river using the formula

[[File: formula.png]]

with:

{|
|u
|the main stream velocity
|-
|y
|a co-ordinate perpendicula to the main stream
|-
|C
|the Chezy coefficient
|-
|h 
|the depth of water
|-
|nu
|the lateral viscosity according to Elder
|-
|d z_S / d x
|the free surface gradient (assumed to be positiv)
|}


This formula is valid, if and only if

* the bottom friction can be described by Chezy's formula (which as a matter of fact is not the best one to describe the bottom friction)
(otherwise use the [[Bed Roughness Parameter Calculator]])

* the effects of lateral turbulent viscosity can be calculated according to Elder's law.

* the flow is stationary in time

* the river is stright i.e. has no curves

* the bottom contours do not change along the river

* which means that the river width is constant

* and of course there is no wind stressing the free surface.

==How to use the Applet==

#The user must define the free surface gradient.
#The user has two possibilities to fill out the table, which is more easy than it seems to, because the table does not need a special format.
#:Every line stands for a profile position which follows the lateral co-ordinate y. The user defines the profile position, the measured water depth and: the Chezy #coefficient OR the velocity depending on the calculation modus.
#:Beginners should use the predefined profiles which are prepared in a drop-down list at the LPA's bottom.
#Press the Calculate button. The table will be filled out with the missing quantity.
#Press the Diagram button and the profiles of the velocity, the Chezy and the water depth will become visible.
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back to [[Lateral Profile Applet]]
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[[Overview]]