EFFECT OF GRAVITY LEVELS ON SALT FINGERS IN DOUBLE-DIFFUSIVE CONVECTION

Author(s):  
Kartika Ahuja ◽  
Om Prakash Singh
2008 ◽  
Vol 65 (3) ◽  
pp. 1095-1097 ◽  
Author(s):  
David M. Schultz ◽  
Adam J. Durant ◽  
Jerry M. Straka ◽  
Timothy J. Garrett

Abstract Doswell has proposed a mechanism for mammatus called double-diffusive convection, the mechanism responsible for salt fingers in the ocean. The physics of salt fingers and mammatus are different. Unlike the ocean where the diffusivity is related to molecular motions within solution, the hydrometeors in clouds are affected by inertial and gravitational forces. Doswell misinterprets the vertical temperature profiles through mammatus and fails to understand the role of settling in volcanic ash clouds. Furthermore, given that mixing is a much more effective means of transferring heat in the atmosphere and given idealized numerical model simulations of mammatus showing that the destabilizing effect of subcloud sublimation is an effective mechanism for mammatus, this reply argues that double-diffusive convection is unlikely to explain mammatus, either in cumulonimbus anvils or in volcanic ash clouds.


2014 ◽  
Author(s):  
Yantao Yang ◽  
Erwin P. van der Poel ◽  
Rodolfo Ostilla-Monico ◽  
Chao Sun ◽  
Roberto Verzicco ◽  
...  

2012 ◽  
Vol 692 ◽  
pp. 1-4 ◽  
Author(s):  
R. W. Schmitt

AbstractSalt fingers are a form of double-diffusive convection that can occur in a wide variety of fluid systems, ranging from stellar interiors and oceans to magma chambers. Their amplitude has long been difficult to quantify, and a variety of mechanisms have been proposed. Radko & Smith (J. Fluid Mech., this issue, vol. 692, 2012, pp. 5–27) have developed a new theory that balances the basic growth rate with that of secondary instabilities that act on the finite amplitude fingers. Their approach promises a way forward for computationally challenging systems with vastly different scales of decay for momentum, heat and dissolved substances.


2015 ◽  
Vol 768 ◽  
pp. 476-491 ◽  
Author(s):  
Yantao Yang ◽  
Erwin P. van der Poel ◽  
Rodolfo Ostilla-Mónico ◽  
Chao Sun ◽  
Roberto Verzicco ◽  
...  

The double diffusive convection between two parallel plates is numerically studied for a series of parameters. The flow is driven by the salinity difference and stabilised by the thermal field. Our simulations are directly compared with experiments by Hage & Tilgner (Phys. Fluids, vol. 22, 2010, 076603) for several sets of parameters and reasonable agreement is found. This, in particular, holds for the salinity flux and its dependence on the salinity Rayleigh number. Salt fingers are present in all simulations and extend through the entire height. The thermal Rayleigh number seems to have a minor influence on the salinity flux but affects the Reynolds number and the morphology of the flow. In addition to the numerical calculation, we apply the Grossmann–Lohse theory for Rayleigh–Bénard flow to the present problem without introducing any new coefficients. The theory successfully predicts the salinity flux both with respect to the scaling and even with respect to the absolute value for the numerical and experimental results.


Author(s):  
Pierre Dupont ◽  
O. Gorieu ◽  
Hassan Peerhossaini ◽  
M. Kestoras

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