The Effect of Domain Length and Initialization Noise on Direct Numerical Simulation of Shear Stratified Turbulence DOI Creative Commons

Vashkar Bernard Palma,

Daniel G. MacDonald, Mehdi Raessi

et al.

Fluids, Journal Year: 2024, Volume and Issue: 9(8), P. 171 - 171

Published: July 27, 2024

Direct numerical simulation (DNS) has been employed with success in a variety of oceanographic applications, particularly for investigating the internal dynamics Kelvin–Helmholtz (KH) billows. However, it is difficult to relate these results directly observations ocean turbulence due significant scale differences involved (ocean shear layers are typically on order tens hundreds meters thickness, compared DNS studies, one centimeters). As efforts continue inform our understanding geophysical-scale by extrapolating results, important understand impact model setup and initial conditions resulting turbulent quantities. Given that measurements, whether through microstructures or other techniques, can only provide estimates averaged TKE quantities (e.g., dissipation buoyancy flux), may be necessary compare mean derived from (i.e., across more complete billow evolutions) measurements. In this study, we analyze effect domain length velocity noise Domain important, as dimensions not integer multiples natural KH wavelength compress stretch billows their energetics. The addition random field often used trigger suppress secondary instabilities; however, energetics largely unknown. conclude lengths 1.5 times less affect factor two more. We also increasing amplitude decreases energetics, but different realizations have an even greater than amplitude. These should considered when designing experiment.

Language: Английский

Influence of stratified shear instabilities on particle sedimentation in three-dimensional simulations with application to marine carbon dioxide removal DOI
Adam J. K. Yang, Mary‐Louise Timmermans, Jason Olsthoorn

et al.

Physical Review Fluids, Journal Year: 2025, Volume and Issue: 10(1)

Published: Jan. 10, 2025

The vertical transport of sediment in marine settings can be influenced by a settling-driven convective instability and velocity shear. We conduct three-dimensional numerical simulations to investigate out surface mixed layer under different shear strengths. show how this is determined competition between the growth (Rayleigh-Taylor) stratified instabilities, provide implications for carbon dioxide removal. In weak scenarios (characteristic difference ΔU<0.05m s−1), Rayleigh-Taylor drives enhanced compared Stokes particle settling; weakly sensitive strength shear, with slowest effective settling absence presence strong (ΔU>0.05m instabilities grow rapidly suppress instability, particles significantly reduced. Furthermore, an increase rate mass decrease. these estimates relate limited potential atmospheric draw down via approaches that rely on dissolution ocean. locked icon Physics Subject Headings (PhySH)Carbon sequestrationKelvin-Helmholtz instabilityMixing geophysical flowsParticle-laden flowsRayleigh-Taylor

Language: Английский

Citations

0
Flow-Flame Interactions in a Solid Fuel Ramjet Combustor DOI

Luca Macarie,

Kristen M. Stava,

Will C. Senior

et al.

AIAA SCITECH 2022 Forum, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 3, 2025

Language: Английский

Citations

0
The Effect of Domain Length and Initialization Noise on Direct Numerical Simulation of Shear Stratified Turbulence DOI Creative Commons

Vashkar Bernard Palma,

Daniel G. MacDonald, Mehdi Raessi

et al.

Fluids, Journal Year: 2024, Volume and Issue: 9(8), P. 171 - 171

Published: July 27, 2024

Direct numerical simulation (DNS) has been employed with success in a variety of oceanographic applications, particularly for investigating the internal dynamics Kelvin–Helmholtz (KH) billows. However, it is difficult to relate these results directly observations ocean turbulence due significant scale differences involved (ocean shear layers are typically on order tens hundreds meters thickness, compared DNS studies, one centimeters). As efforts continue inform our understanding geophysical-scale by extrapolating results, important understand impact model setup and initial conditions resulting turbulent quantities. Given that measurements, whether through microstructures or other techniques, can only provide estimates averaged TKE quantities (e.g., dissipation buoyancy flux), may be necessary compare mean derived from (i.e., across more complete billow evolutions) measurements. In this study, we analyze effect domain length velocity noise Domain important, as dimensions not integer multiples natural KH wavelength compress stretch billows their energetics. The addition random field often used trigger suppress secondary instabilities; however, energetics largely unknown. conclude lengths 1.5 times less affect factor two more. We also increasing amplitude decreases energetics, but different realizations have an even greater than amplitude. These should considered when designing experiment.

Language: Английский

Citations

0