Measurement of Friction Coefficient on a Powder Layer and Fluid Dynamic Study

Flour

We used cake flour in the experiments. The following image is a magnified image of flour. 

A bulk density of the flour used is 0.5103kg/m3 when sieved and 0.7103kg/m3 when compressed.

Appendix Fig. 1. A magnified image of flour used in experiments. Click image for an enlarged view.