We present a new family of spherically symmetric models for the luminous components of elliptical and spiral galaxies and their dark matter haloes. Our starting point is a general expression for the logarithmic slope α(r) = d log ρ/d log r from which most of the cuspy models yet available in literature may be derived. We then dedicate our attention to a particular set of models whose logarithmi...

The relation between the equivalent roughness and different grain size percentiles of the sediment in gravel-bed rivers was determined under the hypothesis that the vertical distribution of the flow velocity follows a logarithmic law. A set of 954 data points was selected from rivers with gravel size sediment or larger, with a non-sinuous alignment and free of vegetation or obstacles. According...

The properties of the mean momentum balance in turbulent boundary layer, pipe and channel flows are explored both experimentally and theoretically. Available highquality data reveal a dynamically relevant four-layer description that is a departure from the mean profile four-layer description traditionally and nearly universally ascribed to turbulent wall flows. Each of the four layers is charac...

During hierarchical clustering, smaller masses generally collapse earlier than larger masses and so are denser on the average. The core of a small mass halo could be dense enough to resist disruption and survive undigested, when it is incorporated into a bigger object. We explore the possibility that a nested sequence of undigested cores in the center of the halo, which have survived the hierar...

Neurons in a variety of species, both vertebrate and invertebrate, encode the kinematics of objects approaching on a collision course through a time-varying firing rate profile that initially increases, then peaks, and eventually decays as collision becomes imminent. In this temporal profile, the peak firing rate signals when the approaching object's subtended size reaches an angular threshold,...

Large-eddy simulation (LES) has become a widely-used method for computation of field-scale environmental flows; however, challenges remain in determining the optimal turbulence closure method. Recently, the concept of explicit filtering and reconstruction has become recognized as a means to obtain more accurate simulation results (Carati et al. 2001, Winckelmans et al. 2001, Stolz et al. 2001, ...

In this work, we propose a single formula for the law of wall, which is dubbed as logarithmic-exponential (LOG-EXP) formula, predicting mean velocity profile in different regions near wall. And then feedforward neural network (FNN), whose inputs and training data are based on new trained wall-modelled large-eddy simulation (WMLES) turbulent channel flows. The direct numerical (DNS) flows used t...

the shape of wake behind a wind turbine is normally assumed to have a hat shape for the models used in wind farm layout optimization purposes; however, it is know from experimental tests and numerical simulations that this is not a real assumption. in reality, the results of actual measurements and detailed numerical simulation show that the velocity in wake region has a s-shape profile. the pr...

a numerical model for two-phase debris flows is developed in this paper, on the basis of understanding of the physical characteristics of debris flows from field investigations and experiments. employing a moving coordinate, the kinetic energy equation of gravel particles in unit volume in debris flow is developed by considering the potential energy of the particles, energy from the liquid phas...