Simulation and Analysis of the Rotating Drum Test

This section provides instructions for running a simulation of the rotating drum test and computing the Angle of Repose (AoR) and its temporal evolution using the provided files.

Introduction

The test consists of measuring the AoR of a granular material flowing in a rotating cylinder as shown in Figure 1.
Figure 1. Determination of the dynamic Angle of Repose test


In order to determine the AoR of the particle bed, a point cloud is first constructed using particle sphere centers, particle centers of mass, or particle mesh nodes as appropriate. The bed free surface is then determined by subdividing a user-defined portion of the domain into a rectilinear grid of bins, identifying the highest particle (with a maximum global Z coordinate) in each bin and conducting a least-squares linear fit to the coordinates of these points as shown in Figure 1.

Measurements are taken for each row of bins along the global X direction as shown in Figure 2, and the analysis is conducted over a period of time to calculate the temporal average and standard deviation of the AoR.
Figure 2. Multiple radial measurements of the AoR at a fixed point in time

Prerequisites

All the requisite files are located at: <Altair installation folder>\EDEM <version>\examples\Calibration Kits\Rotating Drum.

Using the kit

The simulation deck provided can be run directly in EDEM, and the AoR can be automatically obtained via the provided Python script which uses the EDEMpy library of functions to find all EDEM decks in its folder tree and generate plots and results reports per simulation deck, as well as a summary results report for all decks. The analysis settings for the script are defined in the provided text file and listed in Table 1 as follows:
Table 1. Python script settings
Parameter Description
Temporal averaging: start time (s), end time (s), step factor (integer) Specifies the start time (in seconds), end time (in seconds), and the Step Factor that determines the frequency of saved Time Steps to be included in the calculation (as an integer). The values should be comma delimited. The nearest saved Time Steps are used for the start and end of the analysis.
Domain limits: x_min,x_max,y_min,y_max (m) Specifies the global X and Y bounds of the domain used for the analysis (in meters). The values should be comma delimited. Alternatively, you can specify ‘auto’ as a string, in which case the middle half of the surface along its length and width is automatically estimated over the specified time range and used for the analysis.
Bin size in x (m), bin size in y (m) Specifies the length of individual bins in the grid in the X and Y directions (in meters). The values should be comma delimited. Alternatively, you can specify ‘auto’ as a string, in which case the bin length is estimated from the average neighbour distance in the point cloud.
Create results report (yes/no)? Specifies whether individual results reports are written out for every simulation deck and stored in its folder in .csv format.
Summary report? (yes/no) Specifies whether a summary report with the key results for all simulation decks will be produced. The results are written out in the Summary.csv file in the Python script folder.
Plot figures? (yes/no) Specifies whether a plot of the particle bed and surface fits for the last saved time step included in the analysis is created per simulation deck and stored its folder in .png format.

A settings text file is required for each folder containing EDEM simulation decks, and the settings are used to post-process all simulation decks in that folder.

The provided Python script can be executed from EDEM Analyst > File > Run EDEMpy Script, or from the command line. To run the script from the command line, you must ensure that EDEMpy is installed in the relevant Python distribution. For more information about installing EDEMpy, see Install EDEMpy.