This book summarizes unique research findings on the hydrodynamic behavior of ice particles (ice crystals, snow, graupel and hailstones) in the atmosphere. The fall behavior of ice hydrometeors determines how and how fast a mixed-phase cloud can grow or dissipate. The book discusses how the authors used computational fluid dynamics (CFD) methods and numerical simulations to determine these behaviors, and presents these computations along with numerous detailed tables and illustrations of turbulent flow fields. It also examines the implications of the results for the general atmospheric sciences as well as for climate science (since the cloud problem is the source of the greatest uncertainty in model-based climate predictions). As such it allows readers to gain a clear and comprehensive understanding of how particles fall in clouds and offers insights into cloud physics and dynamics and their impact on the climate..
Author(s): Pao K. Wang
Series: Atmosphere, Earth, Ocean & Space
Publisher: Springer Singapore
Year: 2021
Language: English
Pages: 176
City: Singapore
Preface
References
Contents
1 Clouds and Precipitation Particles
1.1 Clouds in the Atmosphere
1.2 Impact of Particle Motions on the Physics of Clouds
1.3 Cloud and Precipitation Particles
1.3.1 Cloud Particles
1.3.2 Precipitation Particles
References
2 Observational Studies of Ice Hydrometeors and Their Fall Behavior
References
3 Physics and Mathematics of the Hydrodynamics of Falling Ice Particles
3.1 Physical Configuration of the Problem
3.2 Numerical Methods of Solving Unsteady Incompressible Navier–Stokes Equation
3.2.1 ANSYS Fluent
3.2.2 Numerical Mesh Configuration
3.2.3 Specifying the Shapes of Ice Particles
3.2.4 Tait–Bryan Angles
3.2.5 Initial Perturbation
3.2.6 Instantaneous Velocity, Terminal Velocity and Reynolds Numbers
3.2.7 Computational Strategy
3.3 Ventilation: A Convective Diffusion Problem
3.4 Terminal Velocity
References
4 Flow Fields and Fall Attitudes of Ice Hydrometeors
4.1 Flow Fields Around Freely Falling Hexagonal Ice Plates
4.1.1 Dimensions of Ice Plates
4.1.2 Terminal Velocities of Falling Ice Plates of 1–10 mm Diameter
4.1.3 Fall Attitudes
4.1.4 Characteristics of Flow Around Falling Ice Plates
4.1.5 Drag Coefficients
4.2 Flow Fields Around Freely Hexagonal Ice Columns
4.2.1 Dimensions of Hexagonal Ice Columns
4.2.2 Fall Patterns of Hexagonal Columns
4.2.3 Stability Diagram
4.2.4 Torque and Flow Fields
4.2.5 Drag Coefficients
4.2.6 Impact of Fluttering and Rotation of Ice Columns
4.3 Stellar and Broad Branch Crystals
4.3.1 Dimensions of Planar Ice Crystals
4.3.2 Flow Characteristics
4.3.3 Fall Attitudes
4.3.4 Vorticity
4.3.5 Terminal Velocity
4.3.6 Drag Coefficients
4.4 Fall Behavior of Snow Aggregates
4.5 Motion of Falling Conical Graupel
4.5.1 Defining the Shape of Conical Graupel
4.5.2 Dimensions of Conical Graupel
4.5.3 Fall Attitudes and Flow Characteristics
4.5.4 Horizontal Displacement
4.5.5 Drag Coefficients
4.6 Spherical Hailstones
4.6.1 Dimensions and Velocities of Hailstones Examined
4.6.2 Flow Characteristics
4.6.3 Drag Coefficients
4.7 Lobbed Hailstones
4.7.1 Mathematical Formulation for Lobed Hailstones
4.7.2 Characteristics of the Flow Fields Around Falling Lobed Hailstones
4.7.3 Drag Coefficients
References
5 Ventilation Effect of Falling Ice Hydrometeors
5.1 Introduction
5.2 Vapor Density Distributions and Ventilation Coefficients
5.2.1 Planar Ice Crystals
5.2.2 Vapor Density Around Falling Smooth Spherical Hailstones
5.2.3 Vapor Distribution Around Falling Lobed Hailstones
References
