New Shell Models for Rayleigh-B´enard Turbulence

抄録

Two new shell models are introduced to investigate a turbulence driven by a thermal instability (Rayleigh-Benard turbulence). One is the nearest neighbour real component model (I) and the other is the nearest and the second neighbour complex component model (II). Using these models, quantities such as a mean value of total fluctuation energy, it’s standard deviation, time averaged wave spectrum, frequency spectrum, the maximum instantaneous Lyapunov exponent are evaluated and the characteristics of turbulence are analyzed. Intermittency nature in the models are also investigated and are compared with results obtained by the model which describes Navier-Stokes turbulence.