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At the end of the Analysis, InfoDrainage evaluates how "healthy" the simulation was (for each Storm and each Phase). To do this, InfoDrainage relies on a number of indicators calculated by the engine.

Flow ContinuityComparison of the total incoming volume (including initial volume) and the total outgoing volume (including the final volume) at the end of the simulation. A discrepancy between the 2 volumes indicate that some volume has been either lost or created during the simulation. A significant value of Flow Continuity error implies a poor confidence in the flow results. Because the pollutant transport is dependent on the flow, a large Flow Continuity error normally results in a large Quality Continuity error.
Quality ContinuityComparison of the total incoming pollutant mass (including initial mass) and the total outgoing pollutant mass (including the final mass) at the end of the simulation. A discrepancy between the 2 masses indicate that some pollutant mass has been either lost or created during the simulation. A significant value of Quality Continuity error implies a poor confidence in the concentration results.
ConvergenceAt each computational time-step, the engine uses an iterative procedure to calculate the updated hydraulic state. After each iteration, the engine checks for the "convergence" of the water levels within the system to determine if the new hydraulic state is acceptable or not. There is a maximum number of iterations allowed to reach convergence (8 iterations by default). If the convergence has not been reached after 8 iterations, the engine keeps the hydraulic state from the last iteration and moves on to the next time-step. However, in this situation there is a high chance that this hydraulic state is not physically valid.

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  • Ensure that inflows into the system are gradually-varying, i.e. avoid a jump from zero inflow to 100 L/s over a short period of time for example.
  • Simple Junction nodes should be used in places where the hydraulic conditions are fairly simple. Consider replacing a Simple Junction by a Manhole where more than 2 connections are meeting, or where a node becomes highly surcharged during the simulation.
  • Outlets need to be treated with caution. The adaptive time-step condition currently ignores outlets (weirs, orifices, gates, etc). If an outlet is behaving badly, it is necessary to reduce the time-step range.

Info
titleFurther Help

In the case that none of the measures described in this page improve the simulation health, please contact the Innovyze Support team to get further help.

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