Narrow Results

The hydrodynamic pressures due to random waves around a pipeline near a rigid bed of slope 1:10 have been measured. The tests were performed for pipelines normal and parallel to the wave direction. These tests were carried out for three gap ratios of the pipeline from the sloping bed. The pressures were resolved in the horizontal and vertical directions and integrated for the force time history in the respective directions. The effects of relative clearance of pipe from the bed and wave steepness on the probability distribution of the forces on the pipeline are reported. The average statistical force ratios as a function of scattering parameter and the variation of the force coefficients as a function of Keulegan–Carpenter number are also presented. The details of the model setup, experimental procedure, analysis of results and discussion are reported in this paper.

Damage to buried pipelines due to complex ground responses has been reported at residential development sites and valley plains with complex ground structures. Three-dimensional (3D) ground amplification analyses using 3D, nonlinear, finite-element methods may be effective in predicting such damage; however, it is often difficult to construct ground structures that are capable of reproducing observational characteristics. In this paper, we propose a 3D ground structure optimization method using a 3000$\times$ forward finite-element dynamic analysis with approximately 0.27 million degrees of freedom, enabled by combining an automated 3D finite-element model-generation method and a fast 3D finite-element wave propagation analysis method. This optimization method is capable of estimating 3D ground structure models that can reproduce observational data characteristics. The effectiveness of the method is shown through an illustrative example.

The flow velocity profiles in most of the central air-conditioning pipelines are, in general, not fully developed flow and difficult to obtain the accurate flow rates by flowmeters, which are used for measuring average velocity. Especially for being at the outlet of an elbow, the accuracy of flow rate by measurement is quite low. Therefore, there are some limitations for measurements of flow rate and velocity profile by the present flow measuring technologies. The objective of this study was to establish an approach on accurate predictions of velocity profiles at different measured locations of central air-conditioning pipelines for nonuniform flow measurements by simulations of computational Fluid Dynamics (CFD). All the velocity profiles will integrate as a database for predictions by neural network algorithm for smart measurement further. In the present work initially, international experiments were employed to validate the accuracy of CFD approach. The calculations were carried out by different turbulence models. The results compared with the experimental data by Realizable $k$-$\epsilon$ turbulence model with less computing resources have great agreements. Realizable $k$-$\epsilon$ turbulence model was, therefore, determined for the predictions of central air-conditioning pipeline. According to various pipings and pipe sizes, the results for three cases show that the velocity profiles in the pipelines would not be symmetrical and has strong secondary flow. Therefore, all of the flow profiles would be integrated and analyzed as a database and assist to get accurately the measured locations of ultrasonic flowmeters. Further, this database will be combined with algorithm of artificial neural network for smart predictions.

The Planck satellite-based telescope, designed to map the microwave sky with unprecedented accuracy, feeds the radiation from the sky to two instruments: the Low Frequency Instrument (LFI) and the High Frequency Instrument (HFI), that together cover the frequency range 27 GHz – 1 THz. The LFI Data Processing Centre (DPC) in Trieste is responsible for the in-flight operations, the data reduction and the scientific processing of LFI. The LFI DPC processing tasks and data products are divided in several levels, starting from the Level 1, that receives the raw telemetry from the instrument, up to the Level 3, that produces maps of the main astrophysical components. In this work we present an overview of the architecture and software frameworks that build the processing Levels of the LFI DPC and that are operational since the Planck launch.