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DOI | 10.1175/JAS-D-17-0371.1 |
Buoyant Motion of a Turbulent Thermal | |
Tarshish, Nathaniel1; Jeevanjee, Nadir2; Lecoanet, Daniel3 | |
2018-09-01 | |
发表期刊 | JOURNAL OF THE ATMOSPHERIC SCIENCES
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ISSN | 0022-4928 |
EISSN | 1520-0469 |
出版年 | 2018 |
卷号 | 75期号:9页码:3233-3244 |
文章类型 | Article |
语种 | 英语 |
国家 | USA |
英文摘要 | By introducing an equivalence between magnetostatics and the equations governing buoyant motion, we derive analytical expressions for the acceleration of isolated density anomalies (thermals). In particular, we investigate buoyant acceleration, defined as the sum of the Archimedean buoyancy B and an associated perturbation pressure gradient. For the case of a uniform spherical thermal, the anomaly fluid accelerates at 2B/3, extending the textbook result for the induced mass of a solid sphere to the case of a fluid sphere. For a more general ellipsoidal thermal, we show that the buoyant acceleration is a simple analytical function of the ellipsoid's aspect ratio. The relevance of these idealized uniform-density results to turbulent thermals is explored by analyzing direct numerical simulations of thermals at a Reynolds number (Re) of 6300. We find that our results fully characterize a thermal's initial motion over a distance comparable to its length. Beyond this buoyancy-dominated regime, a thermal develops an ellipsoidal vortex circulation and begins to entrain environmental fluid. Our analytical expressions do not describe the total acceleration of this mature thermal, but they still accurately relate the buoyant acceleration to the thermal's mean Archimedean buoyancy and aspect ratio. Thus, our analytical formulas provide a simple and direct means of estimating the buoyant acceleration of turbulent thermals. |
领域 | 地球科学 |
收录类别 | SCI-E |
WOS记录号 | WOS:000442845600001 |
WOS关键词 | VERTICAL VELOCITY ; CUMULUS ; CONVECTION ; RESOLUTION ; PRESSURE ; UPDRAFT ; MASSES ; FLUID |
WOS类目 | Meteorology & Atmospheric Sciences |
WOS研究方向 | Meteorology & Atmospheric Sciences |
引用统计 | |
文献类型 | 期刊论文 |
条目标识符 | http://119.78.100.173/C666/handle/2XK7JSWQ/29679 |
专题 | 地球科学 |
作者单位 | 1.Princeton Univ, Atmospher & Ocean Sci Program, Princeton, NJ 08544 USA; 2.Princeton Univ, Dept Geosci, Princeton, NJ 08544 USA; 3.Princeton Univ, Princeton Ctr Theoret Sci, Princeton, NJ 08544 USA |
推荐引用方式 GB/T 7714 | Tarshish, Nathaniel,Jeevanjee, Nadir,Lecoanet, Daniel. Buoyant Motion of a Turbulent Thermal[J]. JOURNAL OF THE ATMOSPHERIC SCIENCES,2018,75(9):3233-3244. |
APA | Tarshish, Nathaniel,Jeevanjee, Nadir,&Lecoanet, Daniel.(2018).Buoyant Motion of a Turbulent Thermal.JOURNAL OF THE ATMOSPHERIC SCIENCES,75(9),3233-3244. |
MLA | Tarshish, Nathaniel,et al."Buoyant Motion of a Turbulent Thermal".JOURNAL OF THE ATMOSPHERIC SCIENCES 75.9(2018):3233-3244. |
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