2D Incompressible Navier-Stocks Data Dimension Description

[FengMingquan-sjtu]

Hi, I downloaded the "ns_incom_inhom_2d_512-0.h5" from the link and tried using the data in my experiments. The data consists of four items, whose names and dimensions are:

Key=force, shape=(4, 512, 512, 2)
Key=particles, shape=(4, 1000, 512, 512, 1)
Key=t, shape=(4, 1000)
Key=velocity, shape=(4, 1000, 512, 512, 2)

I have several questions about them:

1. what's the meaning of the first dimension of all data? E.g. t.shape=(4, 1000), I guess the '1000' means 1000 time steps, but the '4' is unclear.
2. what do the 'velocity' and 'particles' mean? I guess the 'velocity' means the average velocity of the fluid in the grid, and the 'particles' means the average number of particles in the grid. Is it correct?

Thank you!

[finger-monkey]

Hi, do you know how to draw pdebench_examples.PNG? This is the visualization picture shown by the author on the code homepage