## 5 Analysis of Experimental and Simulation Results
### Uniform Water Body Conditions
#### 5.1.1 Case 1 Working Conditions
At 30 s, the thermal jet emerges from a distance of more than 30 cm and floats to the surface of the environmental water body, with similar temperature distribution characteristics as at 25 s, but a large range of temperature difference dissipates when it rises to the surface of the water body. Simulation calculations are performed according to the grid setup size and calculation time step in the irrelevance validation in Section 4.2 to save the temperature field data of thermal jets at 5 s, 10 s, 15 s, 20 s, 25 s, and 30 s in a homogeneous water environment. The results of the Case 1 simulation calculations are shown in Figure 5.  
From the thermal jet temperature field over time trend graph, it is evident that the thermal jet discharge does not exhibit a significant upward trend within the first 5 s. As the thermal jet continues to discharge, there is a noticeable loss of momentum in the horizontal direction, leading to an initial upward diffusion of heat and an expansion of the temperature attenuation region into the surrounding area. Between 10 s and 20 s, vertical movement dominates as a result of horizontal momentum loss and a gradual increase in velocity loss. By 25 s, the buoyancy rate of the thermal jet begins to decrease, and its ascent slows down, causing a lateral diffusion of temperature at different depths. As the jet reaches the water surface, significant changes occur in its lateral temperature diffusion region with serious decay near the surface and disappearance of certain temperature field characteristics. From a comparison of the experimental and simulation results, it is evident that the overall trend of the thermal jet discharge process remains consistent. As the discharge time increases, the horizontal movement of the jet gradually transitions to an upward floating motion, accompanied by a lateral diffusion of the temperature field. Ultimately, the jet floats to the water surface. In consideration of the jet motion trend and temperature field diffusion range, velocity data on the main axis of the jet motion are selected for comparison between experimental and simulation results, as depicted in Figure 6.  
In the horizontal coordinate, floating height refers to the vertical rising height of the jet, and the vertical coordinate refers to the jet velocity magnitude. Figure 4: Temporal variation of the thermal jet temperature field under the experimental conditions. In the process of upward floating, the thermal jet experiences a significant loss in velocity and decays rapidly within 5 cm of the floating height, with the jet velocity decreasing from an initial 0.1 m/s to approximately 0.04 m/s, resulting in a velocity loss of up to 60%. However, during the subsequent 15 cm of upward floating, the jet velocity decays slowly and gradually stabilizes at around 0.03 m/s, accounting for less than 10% in velocity loss. It is evident that while the initial decay of the thermal jet velocity field is rapid, as it floats upwards it begins to decline slowly due to density differences within the water body. This gradual change persists over a long range of floating depth with minimal amplitude variation. Furthermore, both simulation and experimental results exhibit consistent trends in velocity field decay with a maximum error rate of about 5%, maintaining reasonable accuracy and demonstrating good agreement between them.