18.13 2008-08 Release
Table 18.12 outlines the changes made to the default settings for the 2008-08 release and lists commands to revert the setting to those used by the prior major release group (2007-07). All default settings can be reverted to the prior release by using the command, “
| Command Change | Description of Change |
|---|---|
| Uses a new set of defaults for a number of commands. |
The new defaults produce slightly different results, and very slight differences also occur between the three versions offered. For established models run using the 2007-07-XX builds, use |
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The method for interpolating n values where the 2D Manning’s n varies with depth has been enhanced from a linear interpolation of the M (1/n) value to a spline interpolation of the n value. See |
Generally has little effect other than when the flow is predominantly in the depth range that the n value is varying. The new approach offers a smoother transition in n values from one depth to the other. |
|
The default viscosity coefficient is now a combination of a 0.2 Smagorinsky and 0.1 constant coefficient, and there are some enhancements to the application of the viscosity term. See |
This has slight effect for the majority of models. For fine grid models (<2m cell size) with low bed resistance and significant variations in velocity vectors the effect is more pronounced but is still slight. |
| Inertia and viscosity terms are now not transferred across dry cell sides when constructing the coefficients for the solution arrays. This was having the effect of generating a circulation on the other side of the wall (albeit a very weak one), which of course shouldn’t happen! | Generally little effect, but can have some minor influence for urban models where buildings and fences are modelled as solid thin Z lines. |
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1D weir flow has been improved as the water level difference across the weir approaches zero. The new method is more stable. See |
Very little difference other than improved stability. |
| Incorporates minor improvements for transitioning between Regimes A and B, and between inlet and outlet controlled regimes, for circular culverts. | Very little difference other than improved stability. |
| The new automatic selection of cells for 2D SX connections using the 1d_nwk Conn_1D_2D attribute may choose more than one 2D cell. | Very little difference other than improved stability at the pit 2D connections. |
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The default setting for |
Set |