Volume 2 Issue 1

Authors: Z Ahmad; Himanshu Sharma; Bernhard Westrich

Abstract: Block ramps are structures consisting of boulders on steep slope and used for the stabilization of streams by dissipation of energy of flow by means of generating excessive turbulence. This paper deals with experimental study of turbulence over a block ramp. Three-dimensional velocities were measured by acoustic Doppler velocity meter at a constant depth along the block ramp in the developing flow zone. Spiky velocity data were removed using computer code developed in this study for four filtering methods. Out of other filtering methods, the velocity correlation method was found more effective. Spatial variation of turbulence intensities, Reynolds stress, turbulent kinetic energy and skewness coefficients of velocity fluctuations along the length of block ramp were studied. The longitudinal turbulence intensity increases along the ramp length, while the vertical turbulence intensity decreases. Reynolds stresses and turbulent kinetic energy increase along the block rampas a result of development of boundary layer. Skewness coefficients of the longitudinal and transverse velocity components were observed to be uncorrelated with the block ramp length whereas skewness coefficient of vertical velocity component was observed to vary linearly with the length of block ramp.

Keywords: Turbulence; Block Ramps; Spikes; Turbulent Intensities; Reynolds Stress; Turbulent Kinetic Energy


Authors: E. G. Ladopoulos

Abstract: A non-linear real-time expert water management telematics system is proposed, in order to minimize the waste of 15% to 40% of the water supplies in the ground pipe networks, because of the leakage. Such an expert telematics system will work by using the step testing method, in order to be possible to determine the approximate location of leakage for every big urban area. Moreover, in order to handle data in the Workstation of the Central Station (CS) the ARC / INFO Geographic Information Systems (GIS) is used, working under the UNIX-operating system in X-Windows. The proposed real - time expert system will be non-linear in its responses and a part of the programming language will be fourth generation real-time software working under real-time logic.

Keywords: Non-linear Real-Time Expert System; Telematics System; Real-Time Logic; Water Management System; Geographic Information Systems (GIS); Leaks Control; UNIX - Operating System; Centrally Controlled System


Authors: André Luiz Andrade Simões; Harry Edmar Schulz; Rodrigo Melo Porto; John Stephen Gulliver

Abstract: The behavior of the free surface in skimming flows along stepped chutes is investigated for the step ratio 1V:1H. Data were collected using high frequency ultrasound probes. The measurements included mean surface profiles, statistical parameters related to the surface position, aeration inception point, water depth at the inception point and transition length. The measurements were related to turbulence parameters at the free surface. The measurement methodology was adequate for both the black-water and the white-water regions. Characteristic relations are developed for different variables defined for skimming flows. The results demonstrate regions of increasing and decreasing turbulence in the transition between the black-water and the white-water flows, and a region of decay of turbulence, related to the distance needed to attain the quasi-uniform flow of the white-water.

Keywords: Air-Water Free Surfaces; Stepped Chutes; Turbulence; Skimming Flows; Multiphase Flows