Development and validation of a reduced order history force model. (October 2016)

• Record Type: Journal Article
• Authors: Elghannay, Husam A.; Tafti, Danesh K.
• Is Part Of: International journal of multiphase flow. Volume 85(2016)
• Page Start: 284
• Page End: 297
• Publication Date: 2016-10
• Subjects: Particle dynamics -- History/Basset force modeling -- Point force models; Multiphase flow -- Periodicals; Écoulement polyphasique -- Périodiques; Multiphase flow; Periodicals; 620.1064
• DOI: 10.1016/j.ijmultiphaseflow.2016.06.019
• Languages: English
• ISSNs: 0301-9322

Abstract

Highlights: Reduced order history force model is proposed. The model was validated with experimental data of settling, oscillating and bouncing spheres. The model saves both memory resources and compute time as compared to current method. Abstract: The history force model accounts for temporal development in fluid gradients in the viscous region surrounding a particle in point particle methods. The calculation of the history force typically requires storing and using relative velocity information during the life time of the particle. For a large number of particles integrated over large times, history force calculation can become prohibitively expensive. The current work presents a new modeling approach to calculate the history force in which a decay function is applied to a stored cumulative value of the history force. The proposed formulation is equivalent to applying the same function obtained from a constant acceleration assumption to a running average of the acceleration within the memory time of the particle. The new force model is validated with experimental measurements of settling spheres at Reynolds numbers ranging from around one to a few hundreds and at density ratios from 1.2 to about 9.32. More validation work was carried-out with experimental measurements of oscillating spheres at different frequencies and amplitudes, as well as bouncing spheres at different Reynolds numbers and density ratios. The model shows very good agreement with the experiments of settling spheres and reasonable/good agreement with oscillating and bouncing sphere experiments. The proposed model significantly reduces the computational resources required to calculate the history force especially when large number of particles need to be integrated over long times.