I was wondering if it would be possible to make a sticky post for a units example. It seems

that units can be frustrating to figure out for people new to LBM. I did an example below. I had one

question about the pressure conversion and multiplying by rho.

Units example of LBM

Have a 2-D channel flow that is 4 cm long and 1 cm wide

```
___________________________________________
| |
| |
| |
| |
| | 1 cm
| |
| |
| |
|__________________________________________ |
4 cm
```

The grid is 100 x 25

The physical viscosity and rho are knownâ€¦

nu_{Phys} = 0.035 cm^2/s

rho_{Phys} = 1 g/cm

Calculations

dx_{Phys} = 1/25 = 100/4 = .04 cm

assign a value to tau

tau = 1.5

given that nu_{Phys}=dt_{Phys}/(dx_{Phys}*dx_{Phys})*nu_{LB}

and that nu_{LB} = c_s^2(tau-1/2)

dt_{Phys} = nu_{Phys}*dx_{Phys}*dx_{Phys}/c_s^2/(tau-1/2)

dt_{Phys} = .035*.04*.04*3/(1.5-.5)

dt_{Phys} = 0.000168 s

Assume there is an applied pressure at the inlet of

P_{Phys} = 16000 Pa

1 Pa = Kg/m-s^2

P_{LB} = P_{Phys}* 1000g/kg * 1m/100cm * dx_{Phys} cm/LU *dt_{Phys}^2/TU

P_{LB} = 0.00018 g/LU-TU^2

rho_{LB} = rho_{Phys} * dx_{Phys}^3/LU^3

rho_{LB} = 1 gm/cm^3 * .04^3

rho_{LB} = 0.000064 g/LU^3

Does the pressure need to be multiplied by rho at this point???