The drag coefficient is an adimensional number which defines the air resistance for a given shape. It is defined as the drag force (Fd) divided by dynamic pressure (which is 1/2 air density multiplied for the square of the speed v) and multiplied by the reference area A of the shape:

2020年1月15日 · In this work, we employed CFD-DEM simulations to study the behaviour of seven different drag models: three classic models (Wen-Yu, Gidaspow, Di Felice), three developed with Lattice-Boltzmann simulations (Rong, Beetstra, Koch-Hill), and one developed with Direct Numerical Simulations (Tenneti).

2021年7月2日 · This study systematically evaluates drag from a CFD prediction using both momentum and energy equations. The method uses this combination to separate the total drag coefficient into profile and induced drag components.

2012年3月20日 · In this work the main focus was to investigate how a liquid–solid fluidized bed can be modeled with CFD. The experimental system consists of rectangular pipe where the solid bed height and concentration is measured using photographic technique. The fluid flow was driven through a dense grid making the turbulence isotropic.

该模型是常用拖曳力模型中最早最著名的一个，也是各种CFD软件中的默认模型。 适用范围：所有流体-流体系统，最适合直径为2.5mm的球形气泡，但稳定性较差。

For the first time, aerodynamicists dimensional had a tool attached with flow around airfoils, drag can be which to predict flow in the highly nonlinear predicted to transonic within about 5%; for three-dimensional flow regime.

2019年1月25日 · Computational fluid dynamics (CFD) is used to calculate the drag of non-spherical particles. The investigations are carried out based on steady state and transient simulations on a stationary particle, with the exact particle shape in …

The resistance, termed as the drag force (or the drag coefficient in non-dimensional terms), is a strong function dependent on the shape of the car. This suggests the importance of how the fluid (air) particles move around the car and how fast they move along their path.

The drag exerted by trees is typically modelled, within CFD, as a volumetric sink term () of momentum with a quadratic dependence on velocity (Shaw and Schumann, 1992, Raupach et al., 1996, Finnigan, 2000, Nebenführ and Davidson, 2015), (1) where denotes the wind velocity vector (typically the Reynolds-average), is the leaf-area density (Oke ...

3 天之前 · Abstract Transient computational fluid dynamics (CFD) simulations are essential for many industrial applications, but a significant portion of their computational cost stems from the time needed to reach statistical steadiness from initial conditions. We present a novel machine learning-based initialization method that reduces the cost of …