Brindesh Dhruva

Statistics of wind direction and its increments

We study some elementary statistics of wind direction fluctuations in the atmosphere for a wide range of time scales (10−4 sec to 1 h), and in both vertical and horizontal planes. In the plane parallel to the ground surface, the direction time series consists of two parts: a constant drift due to large weather systems moving with the mean wind speed, and fluctuations about this drift. The statistics of the direction fluctuations show a rough similarity to Brownian motion but depend, in detail, on the wind speed. This dependence manifests itself quite clearly in the statistics of wind-direction increments over various intervals of time. These increments are intermittent during periods of low wind speeds but Gaussian-like during periods of high wind speeds.

ANOMALOUS SCALING OF LOW-ORDER STRUCTURE FUNCTIONS OF TURBULENT VELOCITY

It is now believed that the scaling exponents of moments of velocity increments are anomalous, or that the departures from Kolmogorovs (1941) self-similar scaling increase nonlinearly with the increasing order of the moment. This appears to be true whether one considers velocity increments themselves or their absolute values. However, moments of order lower than 2 of the absolute values of velocity increments have not been investigated thoroughly for anomaly. Here, we discuss the importance of the scaling of non-integer moments of order between +2 and

INTERMITTENCY FEATURE OF SHEAR STRESS FLUCTUATION IN HIGH-REYNOLDS-NUMBER TURBULENCE

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On the Intermittency Feature of Shear Stress Fluctuation in Turbulence

, and obtain them from direct numerical simulations at moderate Taylor microscale Reynolds numbers

Is There Scaling in High-Reynolds-Number Turbulence?

R_\lambda\le

Extraction of Anisotropic Contributions in Turbulent Flows

450, and experimental data at high Reynolds numbers

TRANSVERSE STRUCTURE FUNCTIONS IN HIGH-REYNOLDS-NUMBER TURBULENCE

(R_\lambda \approx 10\,000)

Fusion rules in navier-stokes turbulence: First experimental tests

. The relative difference between the measured exponents and Kolmogorovs prediction increases as the moment order decreases towards

The effects of large scales on the inertial range in high-Reynolds-number turbulence

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The effects of large scales on the inertial range in high-Reynolds-number turbulence: arXiv:chao-dyn/9906041v1 24 Jun 1999

, thus showing that the anomaly is manifested in low-order moments as well.