Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 31105
Spectral Analysis of Radiation-Induced Natural Convection in Littoral Waters

Authors: Yadan Mao, Chengwang Lei, John C. Patterson


The mixing of pollutions and sediments in near shore regions of natural water bodies depends heavily on the characteristics such as the strength and frequency of flow instability. In the present paper, the instability of natural convection induced by absorption of solar radiation in littoral regions is considered. Spectral analysis is conducted on the quasi-steady state flow to reveal the power and frequency modes of the instability at various positions. Results indicate that the power of instability, the number of frequency modes, the prominence of higher frequency modes, and the highest frequency mode increase with the offshore distance and/or Rayleigh number. Harmonic modes are present at relatively low Rayleigh numbers. For a given offshore distance, the position with the strongest power of instability is located adjacent to the sloping bottom while the frequency modes are the same over the local depth. As the Rayleigh number increases, the unstable region extends toward the shore.

Keywords: Instability, Spectral Analysis, natural convection, Littoral waters

Digital Object Identifier (DOI):

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1077


[1] E. E. Adams and S. A. Wells, "Field measurements on side arms of Lake," Journal of hydraulic Engineering, vol. 110, pp. 773-793, 1984.
[2] S. G. Monismith, J. Imberger and M. L. Morison, "Convective motions in the sidearm of a small reservoir," Limnology & Oceanography, vol. 35, pp. 1676-1702, 1990.
[3] S. G. Monismith, A. Genin, M. A. Reidenbach, G. Yahel and J. R. Koseff, "Thermally driven exchanges between a coral reef and the adjoining ocean," J. Phys. Oceanogr., vol. 36, pp. 1332-1347, 2006.
[4] D. E. Farrow and J. C. Patterson, "On the response of a reservoir sidearm to diurnal heating and cooling," J. Fluid Mech., vol. 246, pp. 143-161, 1993a.
[5] D. E. Farrow, "Periodically forced natural convection over slowly varying topography," J. Fluid Mech., vol. 508, pp. 1-21, 2004.
[6] D. E. Farrow & J. C. Patterson, "The daytime circulation and temperature structure in a reservoir sidearm," Int. J. Heat Mass Transfer, vol. 37, pp. 1957-1968, 1994.
[7] C. Lei and J. C. Patterson, "Unsteady natural convection in a triangular enclosure induced by absorption of radiation," J. Fluid Mech., vol. 460, pp. 161-184, 2002.
[8] Y. Mao, C. Lei and J. C. Patterson, "Unsteady natural convection in a triangular enclosure induced by absorption - A revisit by improved scaling analysis," J. Fluid Mech., accepted, 2008.
[9] D. E. Farrow and J. C. Patterson, "On the stability of near shore waters of a lake when subject to solar heating," Int. J. Heat Mass Transfer, vol. 36, pp. 89-100, 1993b.
[10] C. Lei and J. C. Patterson, "A direct stability analysis of a radiation-induced natural convection boundary layer in a shallow wedge," J. Fluid Mech., vol. 480, pp. 161-184, 2003.
[11] A. Rabl and C. E. Nielsen, "Solar ponds for space heating," Solar Energy, vol. 17, pp.1-12, 1975.
[12] U. H. Kurzweg, "Stability of natural convection within an inclined channel," Trans. ASME C: J. Heat Transfer, vol. 92, pp. 190-191, 1970.