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Ocean Environment/Sea States
Published in Sukumar Laik, Offshore Petroleum Drilling and Production, 2018
A cold front exists when cold air replaces warm air. The warm air is lifted to ride up over the cold air. When sufficient moisture is present in the warm air and unstable layers of air exist, thunderstorms may be triggered. At times, squall (a wind of 16 knots or higher, sustained for at least 2 minutes) lines containing thunderstorms travel ahead of the front and violent prefrontal weather is produced.
Rigid pavement icing: misting tests on a model pavement column under simulated cold fronts inside a freezer
Published in International Journal of Pavement Engineering, 2022
Taryn DiLorenzo, Omid Habibzadeh-Bigdarvish, Dongfeng Li, Zheng Fang, Andrew Kruzic, Xinbao Yu
A baseline test was first performed to validate the function of the data acquisition system and obtain a baseline temperature response of the pavement column. Three cooling and misting tests were performed, namely cases 1, 2, and 3, to simulate typical weather scenarios observed from field weather data obtained from the DFW airport. A table summarizing the procedures for each test can be found in Table 1. Case 1 test involved a gradual temperature decrease from 4.4 °C to −3.9 °C over 84 h, with misting occurring when the slab surface reached −1.1 °C. Case 2 test involved a sharp temperature decrease from 4.4 oC to −9.4 oC over 24.5 h with misting occurring when the slab surface reached −1.1 oC. Case 3 test involved an actual cold front scenario, which occurred during the testing. Case 3 test was performed by opening the freezer box door to allow the outside air to influence the freezer box environment. This test was performed during a cold front experienced in Texas, with misting occurring when the slab surface reached 0 oC.
A fully coupled seepage–heat transfer model including a dynamic heat transfer coefficient in fractured rock sample with a single fissure
Published in Geomatics, Natural Hazards and Risk, 2021
Ze Zhang, Shuhong Wang, Tianjiao Yang, Dongsheng Wang, Hong Yin
With the injection of low-temperature fluid, convective heat transfer becomes the dominant heat transfer mechanism between the rock and the fracture, the fracture wall begins to cool down, and the cold front gradually expands into the rock. The rock temperature around the fracture entrance decreases rapidly, and the heat absorbed by the fluid gradually decreases. Therefore, a band-shaped low-temperature zone appears and extends toward the exit of the fracture. The shape of this zone depends on the variations of the aperture. As the aperture increases, the low-temperature area near the fracture increases and the amount of convective heat exchange between the fluid and the rock surface increases significantly. Accordingly, the rock temperature near the fracture is greatly reduced, and the maximum temperature drop is almost 30 °C. As the aperture increases, the temperature gradient of the rock near the fracture and the water flow in the fracture increase slightly. Moreover, when the fracture is very narrow, variations of the temperature field by the seepage flow are low. When the aperture becomes greater, the influence of the thermal convection becomes significant. This is especially more pronounced in the middle area, where the temperature gradient gradually decreases. The temperature of the water outlet has a decreasing trend. However, as the aperture increases, the degree of influence on the temperature of the water outlet decreases.
Comparison of aircraft observations with ensemble forecast model results in terms of the microphysical characteristics of stratiform precipitation
Published in Atmospheric and Oceanic Science Letters, 2020
Yuan FU, Hengchi LEI, Jiefan YANG, Jiaxu GUO, Jiangshan ZHU
In this paper, we utilize the Advanced Research version of the WRF model (ARW), version 3.6, including one control member and nine perturbation members, to simulate the process of stratiform precipitation induced by a cold front associated with an upper-level low-pressure trough that occurred on 21 May 2018 in Hebei Province, China. The LWC, IWC, and particle number concentrations obtained during two ascending and one horizontal flight at different altitudes are compared to the ensemble model results. The data are from the ‘Precipitation Enhancement and Hail Suppression in the Eastern Foothills of the Taihang Mountains’ experiment. The main purpose of the study is to expand the application of ensemble forecasting and evaluate the prediction ability of ensemble modeling to simulate cloud microphysical properties.