Previous analyses of very high frequency (VHF) LightningMappingArray (LMA) observations relative to the location of deep convective updrafts have noted a systematic pattern in flash characteristics. In and near strong updrafts, flashes tend to be smaller and more frequent, while flashes far from strong vertical drafts exhibit the opposite tendency. This study quantitatively tests these past ane...

Background Pressure loss estimation based on the simplified Bernoulli equation frequently misclassifies the severity of aortic stenosis. Consequently, several investigators have on the basis of fluid dynamics theory derived pressure loss indices aimed at improving the clinical approach to pressure estimation [1-3]. However, CMR may offer a stronger alternative. The primary cause of pressure los...

As interest in marine renewable energy increases, observations are crucial for understanding the environments that prospective turbines will encounter. Data from an acoustic Doppler velocimeter in Puget Sound, WA are used to perform a detailed characterization of the turbulent flow encountered by a turbine in a tidal strait. Metrics such as turbulence intensity, structure functions, probability...

The temporal response of a well-developed turbulent boundary layer to the superposition of oscillatory shear has been measured experimentally, over a wide range of frequencies. The response is primarily a periodic organization in magnitude of components of the turbulent velocity field at the forcing frequency. Oscillatory production of turbulence arises predominantly as a modulation of the mean...

“In SOSAA, the horizontal wind velocity (u and v), temperature (T ), specific humidity (qv), turbulent kinetic energy (TKE) and the specific dissipation of TKE (ω) are computed every time step (10 s) by prognostic equations. In order to represent the local to synoptic scale effects, u, v, T and qv near and within the canopy are nudged to local measurement data at SMEAR II station with a nudging...

This note describes a numerically stable version of the improved Mellor–Yamada (M–Y) Level-3 model proposed by Nakanishi and Niino [Nakanishi, M. and Niino, H.: 2004, Boundary-Layer Meteorol. 112, 1–31] and demonstrates its application to a regional prediction of advection fog. In order to ensure the realizability for the improved M–Y Level-3 model and its numerical stability, restrictions are ...

Direct numerical simulation of turbulent homogeneous shear ow is performed in order to clarify compressibility e ects on the turbulence growth in the ow. The two Mach numbers relevant to homogeneous shear ow are the turbulent Mach number Mt and the gradient Mach number Mg . Two series of simulations are performed where the initial values of Mg and Mt are increased separately. The growth rate of...

Decaying homogeneous isotropic turbulence in inertial and rotating reference frames is investigated to evaluate the capability of the lattice Boltzmann method in turbulence. In the inertial frame case, the decay exponents of kinetic energy and dissipation and the low wave-number scaling of the spectrum are studied. The results are in agreement with classical ones. In the frame-rotation case, si...

Optimal control of enclosed environment requires detailed information of air distribution that could be obtained by numerically solving Navier-Stokes equations with a suitable turbulence model. This investigation evaluated the performance of eight turbulence models for transient airflow in enclosed environment using experimental data obtained in a room. The study used the room to create three c...

Observations of turbulent kinetic energy (TKE) dynamics in the ocean surface boundary layer are presented here and compared with results from previous observational, numerical, and analytic studies. As in previous studies, the dissipation rate of TKE is found to be higher in the wavy ocean surface boundary layer than it would be in a flow past a rigid boundary with similar stress and buoyancy f...