Popis: |
The onset of convection was analytically and experimentally investigated for a horizontal water layer cooled from below. The water temperature varied from 0°C to 20°C. The neutral stability curves, predicted for different boundary conditions, are described by three parameters, the Rayleigh-Number Ra, the Nonlinearity N and the Biot-Number Bi. The Nonlinearity N considers the deviation of the real density-distribution from a linear distribution, the case of the well known Benard-problem. The experimental results are in good agreement with the predicted values. |