2D Linear Structures and Breach Modelling in ICM

Dr Duncan Kitts

Innovyze Drainage and Flood Modelling User Day

Wednesday June 25th 2014

Floodplain Structures Increasingly modelling in 2D Structures commonly represented by:-

Mesh Zones • Ignores surcharge and headloss effects • Ignores 2 layer flow

1D Links • Lose momentum • Can introduce instabilities

Now can represent in 2D

Base Linear Structures

Line to represent structures such as walls/weirs within 2D simulations Walls (supersede existing functionality) Weirs (thin plate or broad crested) User control (user defined head-unit flow curve)

The crest can be:- Constant (height or level) Irregular

Porosity, headloss coefficient and lateral friction coefficient can be added

Flow direction can be set to be uni-directional

2D Sluice/2D Bridge Can be associated

with a 2D Base linear structure, eg a wall/weir

Flow calculated on an element face by face basis

2 Layer flow Opening Overtopping

Sluice is rectangular shape, bridge is user-defined shape

2D Sluice/Bridge

2D Sluice/Bridge Linear Structures

Flow type:- Free

• Free flow consistent in free and pressurised situations so smooth flow profile during transitions. Controlled by head difference and momentum.

Controlled • Controlled by standard weir and orifice equations. Flow calculation is based

on head difference.

Orifice • Free flow during free surface conditions and orifice flow during pressurised

conditions. Flow is only based on head difference.

Software Demo-Linear Structures

2D Linear Structure Results

Overtopping and Porous Flow

Opening Flow Total Flow

2D Structure Applications Walls/Porous Walls Weirs Orifice Sluice Bridge/Culvert Flap Valve (using No Reverse flow option)

Breach Modelling Time-Varying Geometry can be added to:-

Inline Banks (allow 1D Breach) Banklines (allow 1D-2D Breach) Base Linear Structures (allow 2D Breach)

Use Real Time Control (RTC) to vary geometry

Real Time Control Specify elevation values for particular time periods Can use RTC for several banks/linear structures or

several RTC for different points on banks/linear structure Height above datum Depth-Subtracted from specified bank level

Can decrease elevation (breach) or increase elevation (build up embankment)

Software Demo-Breach in a Linear Structure

Breach Results Grid View Graph View Section Pick Tool

3D View (with animation)

Summary Can now represent structures in 2D GPU Compatible Full 2D River Model Breach modelling in a range of different dimensions