ESEL Paper Review_20114017
 
By Hong Guo

1,Title and Author

Title: Mathematical modeling of sewers under surcharge for real time control of combined sewer overflows

Authors:Sophie Duchesne, Alain Mailhot*,Emeric Dequidt, jean-Pierre Villeneuve
INRS-Eau, Universite du Quebec, C.P 7500, 2800 Rue Einstein, Sainte-Foy, Quebec, Canada GIV 4C7

2. Summary of Paper

  1. In this paper, the author compares the performance of the paper’s model (a hydraulic model using an implicit discretization scheme to solve simplified continuity and momentum equations) with the USPA EXRAN model and   SUPERLINK model. The results show the advantage of the model that produce faster like the EXTRAN model, and more, give the more stable result regardless of space and time steps used.
  2. Comparison (the paper’s model and EXTRAN model):  the instabilities are not seen at the time of transition from free surface to pressurized flow in the paper’s model in this paper, which is seen in the EXTRAN model. And the global continuity errors for the simulations illustrated are 0.8% in EXTRAN model while 0% in paper’s model. Then we can have a conclusion that the paper’s model, it does not need to regard the chosen time step.
   In a word, the paper’s model has the superiority that there is no needs to be sensitivity to the stability problems and avoid the continuity in surcharged conduits.
  3. Compare with SUPERLINK model: Actually, after the comparison, we can indicate that two of those models have a computational speed within the same order of magnitude. But in other way, the paper’s model shows the better benefit 
when those face with the steep slopes or the time interval between input data is larger

3.Contribution:
   The paper mainly compares the designed model with the EXTRAN and SUPERLINK model. Firstly, we know that for the CSO model, it is very important that the model can show the rapidly solution and produce the table results. Being based on this principle, the paper developed the new faster simulation model and we can see that this model avoid the instability problem and continuity problem which happens in the EXTRAN model.
    And now our team is running the CSO model and the paper’s model give us the useful idea for the future work.