Likely progenitors for the GRBs (gamma-ray bursts) are the mergers of compact objects or the explosions of massive stars. These two cases have distinctive environments for the GRB afterglow: the compact object explosions occur in the ISM (interstellar medium) and those of massive stars occur in the preburst stellar wind. We calculate the expected afterglow for a burst in a Wolf-Rayet star wind ...

Monin-Obukhov theory predicts the well-known log-linear form of the vertical wind speed profile. A turbulence intensity profile can be estimated from this by assuming that the standard deviation of the wind speed is proportional to the friction velocity. Two parameters, namely the aerodynamic surface roughness length and the MoninObukhov length, are than needed to predict the vertical wind spee...

As wind and solar power provide a growing share of Europe's electricity1, understanding and accommodating their variability on multiple timescales remains a critical problem. On weekly timescales, variability is related to long-lasting weather conditions, called weather regimes2-5, which can cause lulls with a loss of wind power across neighbouring countries6. Here we show that weather regimes ...

The performance of the Weather Research and Forecast (WRF) model in wind simulation was evaluated under different numerical and physical options for an area of Portugal, located in complex terrain and characterized by its significant wind energy resource. The grid nudging and integration time of the simulations were the tested numerical options. Since the goal is to simulate the near-surface wi...

Many US states have targets for vastly expanding electricity generation from renewable resources. As installed wind capacity increases, several factors can lead to the curtailment of potential windgenerated electricity. Reliably estimating wind power outputs remains a challenge given the dearth of available hub height-altitude wind speed data and measured outputs from newer turbines. A methodol...

The spectral energy distribution from the X-ray to the very high energy regime (> 100 GeV) has been investigated for the γ-ray binary system PSR B125963/SS2883 as a function of orbital phase within the framework of a simple model of a pulsar wind nebula. The emission model is based on the synchrotron radiation process for the X-ray regime and the inverse Compton scattering process boosting stel...

A procedure is developed to generate a large aerodynamic database suitable for the static stability analysis of launch vehicles in the transonic regime by using the Navier–Stokes equations. Effects of structural deformations are also included using modal representation. It is shown that a large number of cases suitable for design can be computed within practical time limitations by using effici...

The wind wave regime of Tallinn Bay, Gulf of Finland, is analysed with the use of a simplified method of long-term computations of wave fields based on a high-resolution nested WAM model and Kalbådagrund (1991–2000) wind data. The distributions of probabilities for wave heights, annual and seasonal mean wave heights, density of wave energy and its flux (wave power), and 1-year return wave heigh...