Modelling of Plates in Free Fall: Development of a Predictive Trajectory Model by an Experimental and Numerical Approach

Simonsen, Anders Schou

4. term

Energy Engineering, Master

2015

2015-06-03

77 pages

Modelling of non-spherical particles is important in many applications. Currently, the motion of non-spherical particles is modelled using spherical assumptions, as the motion of such particles is well documented. However, using this approach, neither the orientation nor the derivatives with respect to time are taken into account, which is found to be crucial for accurate modelling. This study extends the current framework by investigating plates in free fall using an experimental and numerical approach in order to develop an accurate predictive trajectory model. A CFD-model is developed, which is capable of predicting the trajectory of a given plate in a fast and accurate way. The model was verified by comparison with experimental trajectories. Using the CFD-model, numerous simulations were carried out in a parametric study, where various parameters were varied. A predictive trajectory model was developed, which was primarily based on inviscid and irrotational flow theory. A panel method for predicting added mass and circulation coefficients was developed and coupled with the model. This allowed for accurate modelling of the plate trajectories for a wide range of geometries and densities. The model was compared with an existing regime map from literature, where the motion was classified as a function of Re, which showed good resemblance. A new dimensionless number was proposed for general motion classification for freely falling objects, which yielded more clearly distinguishable regions.

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