## 5 Analysis of Experimental and Simulation Results
### Uniform Water Body Conditions
#### 5.1.4 Case 4 Working Conditions  
For Case 4, the initial velocity of the jet is 0.1 m/s, the water depth is 0.52 m, and the temperature difference with the ambient water body is 10 \({}^{\circ}\)C. In comparison to Case 1, the depth of the jet is doubled while maintaining unchanged initial temperature difference and jet velocity. The changes in the temperature field distribution of the jet discharged in a uniform water environment at 5 s, 10 s, 15 s, 20 s, 25 s, and 30 s are depicted in Figure 11 under the experimental conditions.  
From Figure 11, it is evident that at 5 s, the distance of the thermal jet outgoing is approximately 10 cm with minimal uplift. In the core area of the thermal jet, there is a temperature difference of nearly 10 \({}^{\circ}\)C compared to the surrounding environment. At a distance of 10 cm from the outlet, an uplift in the thermal jet can be observed, and the temperature difference between the thermal jet and ambient water at this position decreases to about 4 \({}^{\circ}\)C. By 10 s, the distance of the thermal jet has increased to close to 16 cm, with an uplift height of about 7 cm. The thermal jet displays more noticeable uplift after rising past 10 cm from the outlet; during this phase, there is a gradual decay in temperature difference between the thermal jet and ambient water body from 4 \({}^{\circ}\)C to about 2 \({}^{\circ}\)C. At 15 s, the distance of the thermal jet is slightly more than 20 cm, and the uplift height is close to 15 cm. Compared with 10 s, the temperature difference between the thermal jet and the ambient water body increased within a range of 1 \({}^{\circ}\)C.  
At 20 s, the distance of the thermal jet is about 30 cm, and the uplift height is 20 cm. Compared with 15 s, there is a slight reduction in the temperature field within a range of 2-4 \({}^{\circ}\)C. At 25 s, the thermal jet reaches a distance of approximately 30 cm, with an uplift height of 25 m. In comparison to 20 s, the temperature difference range of 1\({}^{\circ}\) continues to expand, and the temperature difference dissipates in the rear part of the uplift stage. By 30 s, the thermal jet's outgoing distance exceeds 30 cm, and it floats up to 27 cm. The  
Figure 10: Simulation calculated results of the thermal jet temperature field.  
temperature distribution characteristics are similar to those at 25 s, but there is a larger range of temperature dissipation as it rises to the surface of the water body.  
Based on measurements taken at intervals of 5 s, 10 s, 15 s, 20 s, 25 s, and 30 s under the experimental conditions, Case 3 simulation calculation results are selected for analysis in Figure 12.  
Figure 11: Temporal variation of the thermal jet temperature field under the experimental conditions.  
Figure 12: Simulation calculated results of the thermal jet temperature field.  
When the depth of the jet is doubled, the trend of temperature diffusion in the jet is essentially consistent with the conditions in Case 1. Within 5 s, there is virtually no upward trend in the thermal jet discharge. As the thermal jet continues to discharge, momentum in the horizontal direction is clearly lost and begins to float upwards, causing the temperature decay region to expand in all directions. In the time period from 10 s to 20 s, the temperature field of the thermal jet is predominantly influenced by a vertical floating motion. The horizontal distance of the outgoing jet increases slowly due to a loss of velocity. At around 25 s, the buoyancy rate of the jet begins to decrease and its increase in height slows down. Different depths of thermal jets begin to show lateral diffusion of temperature regions. At 30 s, it is observed that the floating height reached about 26 cm and did not diffuse up to reach the water surface level.