You are using a “Version 1” particle_input.dat which is just a list of numbers. The code in read_particle_input.f looks at the first line of that file to determine what format is used. A new format was defined in MFiX 20, which is indicated with Version 2.0 on the first line. This is described in the manual at:
The advantage of this format is that it allows to either read variables or set a constant value for all particles. That saves having to create files like the sq_input.dat file I constructed above.
read_particle_input.f actually defines 3 implementations, Version 1, Version 2, and Version 3, which doesn’t seem to be documented yet.
The Version 1 code always tries to read the superquadric parameters from sq_input.dat after loading particle_input.dat.
Version 2 does not care at all about superquadric parameters.
And Version 3 has support for SQP parameters being either constant or specified per-particle.
Let’s try upgrading your V1 file to V2:
Version 2 requires a long header, including the instructions, and expects data to start on line 35. So the easiest way is to start with an existing Version 2 file and modify it.
The DEM 3D hopper tutorial uses V2 format so I copied the header from there, and then modified it as follows:
Version 2.0
========================================================================
Instructions:
Dimension: Enter "2" for 2D, "3" for 3D (Integer)
Particles: Number of particles to read from this file (Integer)
For each variable, enter whether it will be read from the file
("T" to be read (True), "F" to not be read (False)). When not read, enter the
default values assign to all particles.
Coordinates are always read (X,Y in 2D, X,Y,Z in 3D)
Phase_ID, Diameter, Density, Temperature are scalars
Velocity requires U,V in 2D, U,V,W in 3D
Temperature is only read/set if the energy equation is solved
Species are only read/set if the species equations are solved, and requires
all species to be set (if phase 1 has 2 species and phase 2 has 4 species,
all particles must have 4 entries, even phase 1 particles (pad list with zeros)
User scalars need DES_USR_VAR_SIZE values
Data starts at line 35. Each column correspond to a variable.
========================================================================
Dimension: 3
Particles: 4500
========================================================================
Variable Read(T/F) Default value (when Read=F)
========================================================================
Coordinates: T Must always be T
Phase_ID: F 1
Diameter: T
Density: T
Velocity: T
Temperature: F (Ignored if energy eq. is not solved)
Species: F (Ignored if species eq. are not solved)
User_Scalar: F (Ignored if no user scalars are defined)
============================================================================================
X (m) Y (m) Z (m) Diameter (m) Density Velocity
============================================================================================
1.34940000E-02 1.10180000E-02 1.55820000E-02 6.42583409E-03 2.65000000E+03 0.00000000E+00 0.00000000E+00 0.00000000E+00
2.69890000E-02 1.10180000E-02 1.55820000E-02 6.42583409E-03 2.65000000E+03 0.00000000E+00 0.00000000E+00 0.00000000E+00
4.04830000E-02 1.10180000E-02 1.55820000E-02 6.42583409E-03 2.65000000E+03 0.00000000E+00 0.00000000E+00 0.00000000E+00
Note that I set Diameter, Density and Velocity enabled (T) because your file contains these. Alternately, you could remove all but the first 3 columns of data and specify the constant density and velocity values in the header.
After doing this I still get the same floating-point exception at
Floating-point exception - erroneous arithmetic operation.
Backtrace for this error:
#0 sq_properties_mod_MOD_sq_volume
at des/sq_properties.f:675
due to shape parameter N being 0.