Demo Breach Iterate Project
The Demo Iteration Flood project is available for all users and can be found in the main menu under Edit projects. This project does not count towards your license.
This project is intended for hydrologists and other water experts.
This project showcases the Flooding Overlay in a iteration mode.
The demo show the iteration functionality in combination with template excels that can change the width of a breach. It also records the object width and flow output between iterations using additional Template Excel panels, as well as a Text Template panel that plots these values in a chart.
Calculations using the Iteration option
The demo project simulates a Dutch polder to demonstrate how a breach can be adjusted while using the iteration option.
There are situations in which we want more control over what width of a breach each iteration according to some condition. By dividing the flooding event into several iteration steps, we can adjust the breach width for each iteration step based on the degree of saturation of the soil. In this way, infiltration can be calculated in a more realistic way.
The purpose of this demo project is to clarify how an iterative calculation can be made. In this case, the infiltration of water during and after a precipitation event was chosen. However, on the basis of this demo project, it should also be possible to calculate other calculations iteratively.
Setup of the Demo Project
The demo project consists of a number of components that are essential for this calculation.
- Combo Overlay
- Flooding Overlay
- Iteration Collector
- Indicator
- Number of Simulation Iterations
- Template Excel Panels
- Template Text Panels
Combo Overlays
Before we create the Flooding event, a number of overlays are created that serve as input for the various iteration steps. At the end of each iteration the combo overlay is updated an serves as the input for the next iteration step. We'll go through the different combo overlays.
Combo Surface U and Combo Surface V
These overlays say something about the initial velocity of the surface water in x and y directions. When water flows down a slope, we want to use the speed at which the water flows at the end of an iteration step as the initial speed at the next iteration step. The input grid is the result of the last calculation. In the formula of this combo overlay, you can see that the formula is aimed at making sure that it computes with the data from the previous time step, unless the previous iteration step was step 0. In that case, 0 is used.
Make sure to check the box "previous" to make sure the Combo Overlay uses the U and V of the previous itertationstep.
The formula in the combo overlay should in this case read: IF(EQ(ITERATION, 0), 0, A)
Combo Surface
The combo Surface gives the last value of the waterlevel on the surface and is input for the next iteration step. If there is no previous iteration step, the value should be 0. Make sure to check the box "previous" to make sure the Combo Overlay uses the values of the previous itertation step.
The formula in the combo overlay Combo Fraction should in this case read:
IF(EQ(ITERATION, 0), 0, A)
Flooding Overlay
When configurating the flooding overlay, the default settings can be used. The exceptions are described below.
Rain Event Duration: Here the the total duration of the calculation is specified. Later this is divided into different iteration steps.
Water System – Water Level: Here the initial water level and the U and V flow are set. Use the option "Advanced: Select Grid Overlay to set initial water level and also flow UV".
The water level is set based on a specific overlay, which is the combo overlay Surface. Similarly, the y and x speed from the combo overlay is used as initial input.
Generated Output Overlays:
- Surface Last Value
- Surface Last U
- Surface Last V
- The number of timeframes is set to 1.
Iteration Collector
The Iteration Collector is a type of overlay. It shows the results of each iteration step. An iteration collector needs an input overlay, in this case it is the Rainfall overlay. Of each iteration step one timeframes will be saved.
An attribute of the Iteration Collector is the Modulus. The Modulus determines how many iterations you store. By default, this is set to 1. This means that only one (the last) result of each iteration step is saved and used as a timeframe in the iteration collector. When the modulus is set to 1, every iteration is stored. When you set the modulus to 2, half of the iteration values are stored.
Indicator
The purpose of the indicator is to set the start and end time of each iteration step of the flooding overlay. To accomplish this, a set of queries is performed. First and foremost, the amount of iteration steps and the total duration of the simulation obtained. This is obtained by using the query SELECT_ITERATIONS_WHERE and SELECT_ATTRIBUTE_WHERE_NAME_IS_RAIN_M_AND_OVERLAY_IS_10_AND_RELATION_IS_WEATHER_AND_INDEX_IS_2.
In this simple situation, the total simulation time will be subdivided into n equal steps, where n is the amount of iterations. The current iteration can be obtained using the query SELECT_ITERATION_WHERE_
The start and end time can then be calculated by multiplying the simulation time by the iteration fractions simulationTime * iteration / iterations and simulationTime * (iteration +1) / iterations. The simulation time for the iteration is then updated by using the update queries UPDATE_OVERLAY_PARTIAL_START_SEC_WHERE_OVERLAY_IS_3 and UPDATE_OVERLAY_PARTIAL_END_SEC_WHERE_OVERLAY_IS_3.
Number of Iterations
The number of iterations can be set via the calculation panel. Here you find the option iteration where you can set the number of iterations. This is set to 1 by default.
Exploring the results
To view the results of the calculation, the Iteration can be played everywhere. The following results can be seen here:
- Water on surface level in meters
- Iteration U and V: The speed of the surface water in either the x or y direction.
Template Excel Panels
The project contains several template panels, three of which are excel panels and one is a text panel. These template panels are all performed on breach areas, of which only one is present in this project.
The template excel panel named Update Attribute Breach Width (Before) is performed at the start of each iteration, indicated by the BEFORE setting, which can be seen in its Template Excel Detail Panel. This Template Excel obtains the current iteration using SELECT_ITERATION_WHERE_, and updates the BREACH_WIDTH area to 3 + iteration using UPDATE_AREA_BREACH_WIDTH_WHERE_NAME_IS_BREACH_WIDTH_AND_AREA_IS_ID
The template excel panel named Store Breach Width in Width At (After) is performed at the end of each iteration, indicated by the AFTER timing setting. This template excel obtains the OBJECT_WIDTH_OUTPUT attribute from the Breach Area at each iteration, using the query SELECT_ATTRIBUTE_WHERE_AREA_IS_ID_AND_NAME_IS_OBJECT_WIDTH_OUTPUT_AND_ITERATION_IS_X. Queries with iterations clauses are cached and only executed when a particular iteration is active. The resulting values can then be concatenated into an array and stored under the attribute BREACH_WIDTH_AT using UPDATE_AREA_BREACH_WIDTH_AT_WHERE_AREA_IS_ID
The template excel panel named Store Breach Flow (After) is also performed at the end of each iteration, indicated by the AFTER timing setting. This template excel obtains the OBJECT_FLOW_OUTPUT attribute from the Breach Area at each iteration, using the query SELECT_ATTRIBUTE_WHERE_AREA_IS_ID_AND_NAME_IS_OBJECT_FLOW_OUTPUT_AND_ITERATION_IS_X. The resulting values can then be concatenated into an array and stored under the attribute BREACH_FLOW_AT using UPDATE_AREA_BREACH_FLOW_AT_WHERE_AREA_IS_ID.
Additional a cumulative flow output is calculated and concatenated similarly, and stored under the attribute BREACH_FLOW_SUM_AT using UPDATE_AREA_BREACH_FLOW_SUM_AT_WHERE_AREA_IS_ID. Finally the BREACH_FLOW_SUM attribute is calculated as a single value and stored in the BREACH_FLOW_SUM attribute using UPDATE_AREA_BREACH_FLOW_SUM_WHERE_AREA_IS_ID
The Template Text panel uses a simple HTML div element and javascript to plot a chart of 3 traces: The Breach Area Width at, Flow at and Flow Sum at. This panel obtains these values by simply requesting the respective attributes of the Breach Area that is linked to the Text Panel instance, using $ATTRIBUTE_BREACH_WIDTH_AT.
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Breach Output Plots for Breach Width, Breach Flow and Breach Cumulative Flow.
