Kinematic Wave Flow Routing Functions Summary 🌊🔍💻

· November 10, 2023

 

Kinematic Wave Flow Routing Functions Summary 🌊🔍💻

The kinwave.c module in EPA SWMM5, updated in version 5.2 (Build 5.2.0), authored by L. Rossman and M. Tryby, focuses on kinematic wave flow routing functions.

Key Features 📌

  • Constants: Includes constants like WX (distance weighting), WT (time weighting), and EPSIL (convergence criterion).
  • Shared Variables: Utilizes shared variables such as Beta1, C1, C2, Afull (full area), Qfull (full flow), and a pointer to the cross-section (pXsect).
  • Main Function: kinwave_execute, responsible for finding outflow over a time step using kinematic wave routing in conduits.
    • Process Flow:
      • Checks for non-conduit links and dummy cross-sections.
      • Normalizes previous flows and inflow, and computes evaporation and infiltration loss rate.
      • Solves the continuity equation for downstream normalized area (aout).
      • Updates flows and areas for the conduit, and returns the number of iterations used.

Continuity Equation Solution 📈

  • solveContinuity function aims to solve the continuity equation for normalized area using the Newton-Raphson root finder.
  • It establishes upper and lower bounds for the area and determines the flow based on these bounds.
  • The function evalContinuity is used to compute the value of the continuity equation and its derivative with respect to normalized area.

Updates and Improvements 🛠️

  • Various updates have been integrated, such as conduit inflow consideration for computing losses, and changes in the arguments to the link_getLossRate function.

Technical Specifications 🖥️

  • Uses standard mathematical and header files (math.h and headers.h), and includes the findroot.h file for root finding functionalities.
  • Employs constants and shared variables to simplify and standardize calculations across the module.
  • Integrates detailed documentation and update history for better understanding and maintenance.

Overall, the kinwave.c module is a crucial part of SWMM5, providing advanced routing calculations for modeling flow in urban drainage systems. 🌆🚰🌧️🔢👨‍💻🔍🌊💧📊🛠️📝🖥️🔄