## 1 Introduction
[PERSON] and [PERSON] [24] conducted numerical simulations using the impinging jet model and four different turbulence models, including the Improved Delayed Detached-Eddy Simulation \(k\)-\(\omega\) (IDDES \(k\)-\(\omega\)), SST, Scale Adaptive Simulation (SAS), and LES. Their goal was to determine the most suitable turbulence model for simulating downburst outflow. The results showed that the dynamic LES turbulence model provided simulated values closest to experimental data and accurately captured velocity at different positions. [PERSON] et al. [25] conducted a validation study of the steady-state RANS turbulence model for an impinging jet at two different Reynolds numbers. They focused on the results  
Figure 1: Flow field structure of a downburst [13]. provided by five different turbulence models: standard \(k\)-\(\epsilon\), REA, RNG, SST, and RSM. Their findings indicated that the accuracy of each turbulence model varied at different locations of the jet and that the REA model predicted velocity with the best overall performance. [PERSON] et al. [26] performed numerical simulations using three meshing methods and five turbulence models: standard \(k\)-\(\epsilon\), REA, RNG, standard \(k\)-\(\omega\), and SST. Their results showed that a fine mesh and the SST model produced simulation results most consistent with experimental data. In addition to studies on downburst wind fields in flat areas, there has also been research on downburst flow over hills. [PERSON] and [PERSON] [27] used the impinging jet model and the standard \(k\)-\(\epsilon\) model to simulate the steady-state wind field of a downburst over a hill. Their results showed good agreement between simulated values and field-measured data. They also found that the wind velocity at the hilltop under a downburst was smaller than that under an atmospheric boundary layer wind field. [PERSON] and [PERSON] [15] studied the effects of radial distance and hill slope on the acceleration factor of a cosine-shaped hill based on impinging jet experiments and numerical simulations. Their results showed reasonable agreement between numerical simulations, wind tunnel tests, and field measurements. They also found that the acceleration factor at the hilltop was directly proportional to the hill slope and inversely proportional to the radial distance. [PERSON] et al. [28] used CFD to simulate the wind field over an embankment under a downburst. Their research showed that speed-up factors were similar at the crest of the embankment but dropped off rapidly behind the crest compared with boundary layer flow. [PERSON] et al. [29] used the impinging jet model to conduct experiments and numerical simulations on the wind field of a downburst over three topographic features: cliffs, triangular hills, and bell mountains. They studied the influence of parameters such as hill slope, radial position, and the diameter of the downburst itself. Their results showed that the acceleration factor was greatly affected by the hill slope and that its maximum acceleration effect could reach about 30%. [PERSON] et al. [30] performed three-dimensional numerical simulations of downburst events over two topographical features (cliffs and bell mountains) using a non-hydrostatic sub-cloud model. They then examined the effect of topography on simulated wind velocity. They estimated the acceleration factor of the downburst and compared it with the acceleration factor of boundary layer wind, showing that the acceleration of downburst wind was lower than that of boundary layer wind. [PERSON] et al. [4] used the Detached Eddy Simulation (DES) method to numerically simulate a downburst over two real terrains. They studied the horizontal and vertical wind speed distribution of the downburst as it passed over the real terrain. Their results showed a significant change in the horizontal wind speed profile above the summit, with the corresponding downburst horizontal wind speed increasing by 25% over flatlands. [PERSON] et al.