Published: Jan. 1, 2022
The saturation ratio determines the growth of cloud droplets by condensation and activation aerosol particles. In a uniform environment, interactions between are well understood. However, presence turbulent mixing causes spatial temporal variability in temperature, water vapor ratio. When applied to cloud, S has been shown broaden droplet size distribution through each having its own rate history. grow or evaporation, heat feedback with altering
Language: Английский
Physics of Fluids, Journal Year: 2023, Volume and Issue: 35(3)
Published: March 1, 2023
The traditional method for obtaining aerodynamic parameters of airfoils by solving Navier–Stokes equations is a time-consuming computing task. In this article, novel data-driven deep attention network (DAN) proposed reconstruction incompressible steady flow fields around airfoils. To extract the geometric representation input airfoils, grayscale image airfoil divided into set patches, and these are transformer encoder embedding. extracted from encoder, together with Reynolds number, angle attack, field coordinates, distance field, multilayer perceptron to predict airfoil. Through analysis large number qualitative quantitative experimental results, it concluded that DAN can improve interpretability model while good prediction accuracy generalization capability different flow-field states.
Language: Английский
Citations
55
Atmospheric chemistry and physics, Journal Year: 2025, Volume and Issue: 25(6), P. 3785 - 3806
Published: April 1, 2025
Abstract. It is known that aqueous haze particles can be activated into cloud droplets in a supersaturated environment. However, haze–cloud interactions have not been fully explored, partly because are represented most cloud-resolving models. Here, we conduct series of large-eddy simulations (LESs) convection chamber using haze-capable Eulerian-based bin microphysics scheme to explore over wide range aerosol injection rates. Results show the slow regime at low rates, where responds slowly an environmental change and droplet deactivation negligible. The fast moderate quickly important. More interestingly, two more regimes observed high rates due interactions. Cloud oscillation driven by mean supersaturation around critical collapse happens under weaker forcing transfers efficiently, leading significant decrease (collapse) number concentration. One special case haze-only regime. occurs extremely activation inhibited, sedimentation balanced rate. Our results suggest their with should considered, especially polluted conditions.
Language: Английский
Citations
1
Journal of Advances in Modeling Earth Systems, Journal Year: 2023, Volume and Issue: 15(2)
Published: Feb. 1, 2023
Abstract The convection–cloud chamber enables measurement of aerosol and cloud microphysics, as well their interactions, within a turbulent environment under steady‐state conditions. Increasing the size chamber, while holding imposed temperature difference constant, leads to increased Rayleigh, Reynolds Nusselt numbers. Large–eddy simulation coupled with bin microphysics model allows influence velocity, time, spatial scales on microphysical properties be explored. Simulations fixed aspect ratio increasing heights H = 1, 2, 4, (for dry conditions only) 8 m are performed. key findings are: Velocity fluctuations scale 1/3 , consistent Deardorff expression for convective implying that turbulence correlation time 2/3 . Temperature other scalar −3/7 Droplet distributions from chambers different sizes can matched by adjusting total injection rate horizontal cross‐sectional area (i.e., 2 constant ratio). Injection aerosols at point versus distributed throughout volume makes no polluted conditions, but lead droplet distribution broadening in clean Cloud growth collision coalescence broader right tail compared condensation alone, this increases magnitude extent monotonically increase height. These results also have implications scaling turbulent, cloudy mixed‐layers atmosphere, such fog layers.
Language: Английский
Citations
17
Journal of Advances in Modeling Earth Systems, Journal Year: 2023, Volume and Issue: 15(5)
Published: April 29, 2023
Abstract Recent in situ observations show that haze particles exist a convection cloud chamber. The microphysics schemes previously used for large‐eddy simulations of the chamber could not fully resolve and associated processes, including their activation deactivation. Specifically, droplet was modeled based on Twomey‐type parameterizations, wherein droplets were formed when critical supersaturation available condensation nuclei (CCN) exceeded explicitly resolved. Here, we develop adapt haze‐capable bin Lagrangian to properly deactivation processes. Results are compared with CCN‐based scheme which We find results from agree well those scheme. However, both significantly differ unless CCN recycling is considered. Haze deactivated can strongly enhance number concentration due positive feedback haze‐cloud interactions particle size distributions more realistic considering solute curvature effects enable representing complete physics process. Our study suggests may have strong impact properties fluctuations comparable mean supersaturation, as case likely atmosphere, especially polluted conditions.
Language: Английский
Citations
12
Atmospheric Research, Journal Year: 2025, Volume and Issue: unknown, P. 108144 - 108144
Published: April 1, 2025
Language: Английский
Citations
0
npj Climate and Atmospheric Science, Journal Year: 2025, Volume and Issue: 8(1)
Published: April 5, 2025
Language: Английский
Citations
0
Proceeding of 5-6th Thermal and Fluids Engineering Conference (TFEC), Journal Year: 2025, Volume and Issue: unknown, P. 705 - 714
Published: Jan. 1, 2025
Language: Английский
Citations
0
Review of Scientific Instruments, Journal Year: 2025, Volume and Issue: 96(5)
Published: May 1, 2025
We present a new experimental facility to investigate the nucleation and growth of liquid droplets ice particles under controlled conditions characterize processes relevant cloud microphysics: rapid expansion aerosol chamber (REACh). REACh is an intermediate size (∼0.14 m3) combining principle with ability probe influence turbulent flows. Water droplet heterogeneous onto seeding aerosols achieved via sudden pressure drop accompanied by temperature drop, which can cause humid air condense into appropriate thermodynamic conditions. features tight control monitoring initial saturation ratio water vapor, identity concentration particles, temperature, pressure, flow mixing, together high speed real-time measurements number. Here, we demonstrate that minimum reached during each be reasonably described thermodynamics dry or moist adiabats for range relative humidities. The number formed overall lifetime are characterized as function vapor ratio. total scales linearly concentration, suggesting all injected serve condensation nuclei. While increases mean decreases result competition available vapor. Theoretical considerations provide quantitative prediction over repetition rate experiments perform will permit extensive characterization processes, including onset growth, importance turbulence fluctuations. leverage capabilities this explore wide physical parameters encompassing regimes microphysics.
Language: Английский
Citations
0
Journal of Fluid Mechanics, Journal Year: 2022, Volume and Issue: 944
Published: July 5, 2022
The objective of this work is to investigate the interaction turbulence with nonlinear processes particle nucleation and growth that occur in reaction crystallisation, also known as precipitation. A validated methodology for coupling population balance equation direct numerical simulation turbulent flows employed simulating an experiment conducted by Schwarzer et al. ( Chem. Engng Sci. , vol. 61, no. 1, 2006, pp. 167–181), where barium sulphate nanoparticles are formed mixing chloride acid a T-mixer, spatial resolution resolved down Kolmogorov scale. unity Schmidt number assumed, since at present it not possible resolve Batchelor scale realistic numbers (order 1000 or more). probability density function, filtered averages distribution time length scales all examined order shed light on interplay Separate Damköhler defined both found be close unity, indicating process neither nor kinetics controlled. evaluated compared show importance resolving bursts. In addition, zones different rate-determining mechanisms identified. ultimate aim precipitation obtain control over product size distribution, study elucidates synergistic competing roles mixing, outcome discusses implications modelling.
Language: Английский
Citations
13
Geophysical Research Letters, Journal Year: 2023, Volume and Issue: 50(3)
Published: Jan. 24, 2023
Abstract The exchange of enthalpy and momentum at the air‐sea interface is an important process in tropical cyclone (TC) development intensification, effects sea spray have long been uncertain, particularly high wind speeds. Here we use a coupled large‐eddy simulation Lagrangian cloud model to run high‐resolution simulations idealized, spray‐laden TC boundary layer. Simulations are performed with without generation, using realistic generation function over speeds relevant TCs. We show that C D not affected by droplets 10‐m up 48 m s −1 . E H modified during initial transient adjustment stage, but quickly relax back their unladen values due surface layer saturation. This relaxation occurs faster for higher winds, because increased concentration more rapidly saturates
Language: Английский
Citations
6