Based on the Binder-Schmidt method (see [BK97]), the following boundary is defined for the factor (Fourier number) from equation 18:

$$\frac{\Delta t \cdot a}{\Delta r^2} \leq \frac{1}{2} \tag{Equation 18}$$

The following minimum value is specified for the axial number of segments:

$$M_{min} = N^2 \cdot 2 \cdot \frac{\lambda}{\rho \cdot c_p} \cdot \frac{L}{v_{ab} \cdot R^2} \tag{Equation 19}$$