Turbulens och supraglacial meandring

Sammanfattning: The fieldwork was carried out on Bas Glacier d'Arolla during two days in August 1996. The aim of the study was to verify the existence of a relationship between turbulence and meander geometry according to the theory of Yalin (1992). Turbulence was measured by recording temperature fluctuations in one straight section and one curved section of the supraglacial stream. Temperature series was interpreted by frequency analysis. Peaks of the same frequency were found in the frequency diagrams obtained from the different measuring points recorded at the same time. The inverse frequency or period is used to calculate the estimated meander wavelength. It was indicated that the estimated meander wavelength was well in accordance with the true meander wavelength. The validity of a theory of minimum entropy production by river meandering was tested for meandering streams on ice. It was found that the "law of least time rate of energy expenditure" presented by Yang (1971) is not applicable on supraglacial streams.