Welcome to Guenter Ahlers' Group
From left to right: Daniela Narezo-Guzman, Guenter Ahlers, and Ping Wei (June 2014, Goettingen, Germany)
Ping`s rotating convection apparatus (Photo Credit: Sonia Fernandez March 2015)
Turbulence in thermally driven convection
When a fluid is heated from below, convection will occur when the temperature gradients are large enough. At even much larger temperature differences, the convective flow becomes so vigorous that the velocity field is turbulent (for a review of this phenomenon written for an general audience of physicists, please see a recent article in the open-access journal Physics). Turbulent convection is an important process in many respects. It occurs naturally in the Earth's atmosphere and oceans and thus has short-term as well as long-term impact on climate and weather. It occurs in the Earth's mantle and contributes to the motion of continental plates and to vulcanism. In the outer core of the Earth it determines the magnetic field that protects us from cosmic radiation. It is the important heat-transport mechanism in an outer layer of the Sun and thus affects the temperature of our environment. It plays a significant role in many industrial processes, where its enhancement or inhibition may have significant economic consequences. It is a common phenomenon in everyday life which provokes fascination for the non-specialist.
In order to make progress toward understanding complex phenomena such as those mentioned above, idealized laboratory systems often are used because they permit quantitative experimental studies of specific aspects of the problem. We study this turbulent state under quantitatively controlled laboratory conditions at temperature gradients which exceed the one at onset by factors from ten thousand up to a billion. Our main emphasis has been on turbulent heat transport measurements, on studies of thermal boundary layers near the top and bottom confining plates, and on investigations of large-scale flows in this system. If you are interested in learning more about this topic, you can look at a talk given on March 30 2000 at the KITP or at a more recent talk given on April 13 2005 at the Center for Interdisciplinary Research in Fluid Mechanics.
- Physics Department
- Kavli Institute for Theoretical Physics
- UC Santa Barbara
APS Topical Group on Statistical and Nonlinear Physics
- APS Home Page
Guenter Ahlers/ email@example.com