Loading...

Microgravity modulation effects on free convection problems LBM simulation

Javadi, K ; Sharif University of Technology

673 Viewed
  1. Type of Document: Article
  2. DOI: 10.1063/1.5019798
  3. Abstract:
  4. In this paper, microgravity modulation effects on free convection in a cavity are investigated using the lattice Boltzmann method. In order to create microgravity modulation, a sinusoidal time-dependent function is considered. Parameters of the flow are chosen such that the maximum Rayleigh number approaches 106. The natural frequency of the system is obtained at first. Afterwards, effects of different frequencies on the flow and heat transfer fields are investigated in detail. Results are presented in four different frequency ratios categorized as (1) ω∗=1200, 1100, 120, and 110; (2) ω∗=18, 15, 13, and 12; (3) ω∗ = 0.75, 0.85, and 0.95; and (4) the last one is considered for natural frequency as a special case of ω∗ = 1. Furthermore, the fast Fourier transformation is used to describe the cavity flow behavior. The results indicated that at low frequency, the system has enough time to adapt itself with the gravity modulation while historical effects do not disappear. Increasing the frequency changes the behavior of the system and different flow patterns appear. Finally, at the natural frequency (ω∗ = 1), all system modes are stimulated and a strange flow pattern is formed. © 2018 Author(s)
  5. Keywords:
  6. Computational fluid dynamics ; Flow patterns ; Microgravity ; Microgravity processing ; Modulation ; Natural convection ; Natural frequencies ; Convection problem ; Different frequency ; Fast fourier transformations ; Flow and heat transfer ; Gravity modulation ; Lattice boltzmann method ; Modulation effects ; Time-dependent functions ; Heat transfer
  7. Source: Physics of Fluids ; Volume 30, Issue 1 , 2018 ; 10706631 (ISSN)
  8. URL: https://aip.scitation.org/doi/10.1063/1.5019798