2024-04-17T01:59:36Z
https://ynu.repo.nii.ac.jp/oai
oai:ynu.repo.nii.ac.jp:02000230
2024-02-05T01:06:46Z
500:501
Direct numerical simulations of compressible isothermal turbulence in a periodic box: Reynolds number and resolution-level dependence
Yoshiki, Sakurai
Takashi, Ishihara
0000-0002-4520-6964
Compressible flows, Turbulence, Direct numerical simulations, Fluid Dynamics
A series of direct numerical simulations (DNSs) of forced compressible isothermal turbulence in a periodic box are conducted by using an eighth-order compact finite-difference scheme to study the Reynolds number and resolution-level (kmaxη) dependence of the statistics of the compressible turbulence, where kmax=√3N/2,η the Kolmogorov length scale. The number of grid points N^3 and the Taylor microscale Reynolds number Rλ are up to 4096^3 and 853, respectively, and the turbulent Mach number and the ratio of dilatational to solenoidal root-mean-square velocities are approximately 0.3 and 0.4, respectively. The DNSs have shown that the energy spectrum for the compressible isothermal turbulence increases to a higher wave-number range of kη>1 with increasing resolution levels suggesting a k^−3 scaling of its dilatational component; however, the energy spectrum and its solenoidal and dilatational components for kη<1 are not sensitive to resolution levels provided that kmaxη≳2. When the solenoidal quantities are used for normalization, the solenoidal component of the energy spectrum and the solenoidal dissipation rate agree well with those gathered from the DNSs of incompressible turbulence. DNS studies indicate that the normalized dilatational component of energy dissipation is still finite nonzero for large Rλ values (as opposed to an expectation from the result by John et al. [J. Fluid Mech. 920, A20 (2021)]). The PDFs of the solenoidal component of pressure fluctuations agree with those of incompressible turbulence. However, a close study shows that the solenoidal pressure and enstrophy fluctuations in compressible isothermal turbulence are consistently less intermittent than those in incompressible turbulence. The impact of bulk viscosity on the energy spectrum is examined using the DNSs of compressible isothermal turbulence with nonzero bulk viscosity.
journal article
American Physical Society
2023-08-28
VoR
application/pdf
Physical Review Fluids
8
2469990X
https://ynu.repo.nii.ac.jp/record/2000230/files/Sakurai&Ishihara(2023,PRF).pdf
eng
https://doi.org/10.1103/PhysRevFluids.8.084606
open access