## 2 Numerical Method
### Model Verification
#### 2.5.2 Experimental Verification  
In order to verify the accuracy of the model, the piston wind velocity in the transport lane under the operation of double cages in the shaft was measured. The measured location is arranged in a 1584.0 m transport lane. The 1584.0 m lane is the main transportation lane and is used to connect the upper and lower middle sections and the new and old ventilation systems. The lane also leads to the main production area and is one of the most important air supply lines. This measurement is to obtain the wind speed changes of some representative measuring points in the lane caused by the piston wind of cage operation. Taking the intersection surface of the 1584.0 m transport lane and main intake shaft as the starting measurement point, a measuring point is set every 10.0 m along the horizontal  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Item** & **Parameter Setting** \\ \hline \hline \multicolumn{2}{c}{General} \\ \hline \hline \multirow{3}{*}{Solver} & Pressure-Based \\  & Absolute-Velocity \\  & Transient-Time \\ \hline \hline \multicolumn{2}{c}{Models} \\ \hline \hline Models & SST \(k\)-\(\omega\) Turbulence Model \\ Energy & Off \\ \hline \hline \multicolumn{2}{c}{Materials} \\ \hline \hline Material Type & Fluid \\ Density & 1.255 (kg/m\({}^{3}\)) \\ Viscosity & 1.7894 \(\times\) 10\({}^{-5}\) (kg/m s) \\ \hline \hline \multicolumn{2}{c}{Boundary Conditions} \\ \hline \hline Inlet Boundary Type & Velocity-inlet \\ Inlet Velocity Magnitude & 4.4 m/s \\ Outlet Boundary Type & Free Pressure-outlet \\ Boundary Type of Cage and Lane Wall & Wall \\ \hline \hline \multicolumn{2}{c}{Dynamic Mesh} \\ \hline \hline \multicolumn{2}{c}{Spring-based Smoothing Method} \\ \hline \hline \multicolumn{2}{c}{Local-remeshing Method} \\ Type of cage movement & Rigid body motion-Profile file \\ \hline \hline \multicolumn{2}{c}{Solution Methods} \\ \hline \hline \multicolumn{2}{c}{Pressure-Velocity Coupling} \\ \hline \hline \multicolumn{2}{c}{Specific Dissipation Rate} & Second Order Upwind \\ Time Step Size & 0.01 s \\ \hline \hline \end{tabular}
\end{table}
Table 2: Calculation model parameter setting.  
center line of the 1584.0 m lane to the direction of production area, a total of 6 measuring points, and the location of measuring points is shown in Figure 4.  
Only shaft ventilation was measured velocity of 4.4 m/s, cage at a speed of 10 m/s, uniform operation of 48.5 s through the main intake shaft elevation 1374.0\(-\)1854.0 m, 1584.0 m transport lane wind speed. The wind speed measurement of each measuring point is carried out simultaneously by the point measurement method. The measuring instruments mainly include the ventilation multi-parameter detector (JYF-4), my electronic anemometer (DFA-2), handheld laser range finder (HT-307) and mechanical stopwatch (JM-504).  
Figure 4: Diagram of measured and simulated wind speed.  
Figure 3: Time-varying curve of wind speed at the outlet of 1584.0 m transport lane with different mesh schemes.  
The measured wind speed values and simulated wind speed values of 6 measuring points are dimensionless [27; 28] and compared respectively, and the results are shown in Figure 5. From the figure, we can see that the error of the measuring point closer to the shaft is large, and the error of the measuring point farther away from the shaft is decreasing. After calculation, the average velocity coefficient error between the simulated value and the measured value at each measuring point of a, b, c, d, e and f is 14.40%, 10.36%, 9.06%, 8.07%, 6.29% and 5.75% respectively. The average velocity coefficient error of each measuring point is less than 15.0%, which can verify the accuracy of the model. It shows that it is feasible to use the SST \(k\)-\(\omega\) turbulence model to simulate the change of piston wind with time series and its influence on the air flow of transport lanes.