韩梦涛

副研究员(自然科学)    Supervisor of Doctorate Candidates    Supervisor of Master's Candidates

  • Professional Title:副研究员(自然科学)
  • Gender:Male
  • Status:Employed
  • Department:School of Architecture and Urban Planning
  • Education Level:Postgraduate (Doctoral)
  • Degree:Doctoral Degree in Engineering
  • Alma Mater:The University of Tokyo, Japan

Paper Publications

M. Han. Effect of Time Steps on Accuracy of Indoor Airflow Simulation Using Lattice Boltzmann Method.

Release time:2022-06-20Hits:
  • Indexed by:
    Journal paper
  • Document Code:
    21486
  • Journal:
    JOURNAL OF TONGJI UNIVERSITY(NATURAL SCIENCE)
  • Included Journals:
    EI
  • Place of Publication:
    上海
  • Discipline:
    Engineering
  • First-Level Discipline:
    Architecture
  • Document Type:
    J
  • Volume:
    50
  • Issue:
    6
  • Page Number:
    793-801
  • ISSN No.:
    0253-374X
  • Key Words:
    wind engineering; lattice Boltzmann method; time steps; compressibility errors; over relaxation;large-eddy simulation
  • CN No.:
    31-1267/N
  • DOI number:
    10.11908/j.issn.0253-374x.21486
  • Date of Publication:
    2022-06-01
  • Abstract:
    Lattice Boltzmann method-based large-eddy simulation (LBM-LES) is a new method to solve turbulence problems in recent decades. However, improper time step settings may affect the simulation accuracy of LBM-LES. This paper first analyzed and summarized the impact of time step δt on the results of LBM-LES, theoretically. An oversized δt will cause compressibility error in the velocity field, while a too small δt can lead to the over-relaxation colliding mode, causing the numerical oscillation of velocity field. Subsequently, LBM-LES simulations of an isothermal indoor airflow case were conducted to discuss these errors quantitatively. The results show that a large δt leads to a sharp density change, and the velocity field in the regions where the Mach number (M) in the lattice Boltzmann unit exceeds 0.3 showing that there are obvious compressibility errors. Meanwhile, a too-small δt causes apparent numerical oscillations of both time-averaged and fluctuating velocities. This phenomenon is more significant when the grid resolution is higher. Therefore,it is suggested that δt should be small enough to ensure M<0.3 in the maximum velocity regions, based on which, a larger δt should be utilized to prevent numerical oscillations.
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