Drag Force Model Reference

Drag Coefficient Properties

Simcenter STAR-CCM+ calculates the drag force using drag coefficients. It is impractical to determine these drag coefficients spatially, so Simcenter STAR-CCM+ uses experimental and theoretical correlations to obtain suitable values.

Dimensions

The dimensionality of the drag coefficient (read-only).

Method

Selects the method for specifying the drag coefficient.

Method	Corresponding Method Node
Clift Defines the drag coefficient using the Clift correlation. Use this method for cylindrical particles. This option is only available with the Cylindrical Particles model.	Clift
Di Felice Defines the drag coefficient using the Di Felice correlation. Use this method for dense particulate flow. This option is only available with the Two-Way Coupling Lagrangian phase model.	Di Felice
Field Function Defines the drag coefficient using a field function, which is typically user-defined. All other drag coefficient methods are also available as field functions. As a result, you can combine the Simcenter STAR-CCM+ built-in drag coefficients with your own calibration factors in a user-defined field function. For example: 0.5*$ParticleGidaspowDragCoefficient	Field Function
Gidaspow This method can be used to simulate flow through fluidized beds where the initial packing of particles transitions to low-volume fractions. Use for diluted flows, where other drag models can underpredict the drag in these flow regimes. The Gidaspow drag coefficient method [99] is a combination of the Wen Yu and Ergun methods. A cutoff void fraction determines the point at which one method switches to the other. Eqn. (2973) (Wen Yu) and Eqn. (2974) (Ergun) in the Formulation section are the relevant method equations.	Gidaspow Gidaspow Drag Coefficient Method Properties Exponent The Wen-Yu power exponent (Eqn. (2974)). Cutoff Void Fraction The void fraction cutoff, ${\nu }_{min}$ in Eqn. (2973), for the transition between the Wen-Yu model and the Ergun equation.
EMMS The EMMS (energy minimization multi-scale) correlation is available only for DEM solid particles. Suitable for applications for modeling fluidized bed systems where the influence of heterogeneity from particle clusters becomes significant.	Particle Type Selects one of the following methods for specifying the solid particle type: Geldart A Sets the particle type to Geldart A particles. These (aeratable) particles are fine, cohesive powders with a size and density range based on Geldart powder groups for fluidization. Geldart B Sets the particle type to Geldart B particles. These (sand-like) particles are less cohesive than Geldart A particles, with a size and range based on Geldart powder groups for fluidization. Fluidization Regime Selects one of the following methods for specifying the flow regimes relative to the fluidization: Bubbly Available only for the Geldart A particle type. Applies to cases where the fluid velocity leads to the formation of bubbles within the bed. This regime is characterized by intermittent bubbling and solid particles movement. Fast Applies to cases where the fluid velocity through the bed is greater than the minimum fluidization velocity, leading to a turbulent behavior of solid particles. Pneumatic Applies to cases with high fluid velocity where the particle bed expands, lifting and suspending solid particles within the conveying medium, resulting in a fluid-like behavior. This approach is well-suited for modeling pneumatic conveyors.
Haider & Levenspiel Defines the drag coefficient using the Haider & Levenspielt correlation. Use this method for non-spherical particles with $\mathrm{Re}<2.6\times {10}^5$ .	Haider & Levenspiel
Schiller-Naumann Defines the drag coefficient using the Schiller-Naumann correlation, which is one of the standard Lagrangian drag coefficient methods.	Schiller-Naumann