(launcher_introduction_simple_case_problem)=
# Presentation of the problem

```{math}
:label: flowrate_function

y = f(x) = \frac{2 \pi T_u\left( H_u - H_l\right)}{\ln(\frac{r}{r_{\omega}})\left[ 1 + \frac{2 L
T_u}{\ln(\frac{r}{r_{\omega}}) r_{\omega}^2 K_{\omega}} + \frac{T_u}{T_l}\right]}
```