Abstract
The choice of the computational time step (dt) value and the method for setting dt can have a bearing on the accuracy and performance of a simulation, and this effect has not been comprehensively researched across different simulation conditions. In this study, the effects of the fixed time step (FTS) method and the automatic time step (ATS) method on the simulated runoff of a distributed rainfall–runoff model were compared. The results revealed that the ATS method had less peak flow variability than the FTS method for the virtual catchment. In the FTS method, the difference in time step had more impact on the runoff simulation results than the other factors such as differences in the amount of rainfall, the density of the stream network, or the spatial resolution of the input data. Different optimal parameter values according to the computational time step were found when FTS and ATS were used in a real catchment, and the changes in the optimal parameter values were smaller in ATS than in FTS. The results of our analyses can help to yield reliable runoff simulation results.
Highlights
In the numerical analysis of water flows, the computational time step has mainly been studied from the perspective of a stable convergence of the solution
As there was no observed flow for the calculation of peak flow’s percentage error (PPE) for the virtual catchment in Table 4, the peak flow from when the dt was 1 min in each virtual rainfall was used as the observed flow
The peak flows varied according to the dt values, and their differences became smaller as the amount of rainfall increased for both fixed time step (FTS) and automatic time step (ATS)
Summary
In the numerical analysis of water flows, the computational time step (dt) has mainly been studied from the perspective of a stable convergence of the solution. The first is the fixed time step (FTS) method, in which the dt is fixed for the entire simulation, and the second is the automatic time step (ATS) method [1,2], in which the dt value is dynamically changed during the simulation. When ATS is used, only the initial value of the dt needs to be set, and the dt is automatically calculated normally using von Neuman stability conditions [3,4] or Courant–Friedrich–Lewy (CFL) conditions [5,6]. The von Neuman conditions use a Fourier series when performing finite difference analysis on a linear partial differential equation, and they are mainly employed in explicit solutions. The choice of the dt value and the method for setting dt can have a bearing on the accuracy and performance of the simulation, and this effect has not been comprehensively researched across different simulation conditions
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
