Flow-induced pulsations in resonant pipe systems with two closed side branches in cross configuration are considered. These pulsations, commonly observed in many technical applications, are self-sustained aeroacoustic oscillations driven by the instability of the flow along the closed branches. Detuning of the acoustic resonator is often considered as a possible remedial measure. Although this ...

A test system for water distribution was used to evaluate the stability and effectiveness of three residual disinfectants--free chlorine, combined chlorine, and chlorine dioxide--when challenged with a sewage contaminant. The test distribution system consisted of the street main and internal plumbing for two barracks at Fort George G. Meade, MD. To the existing pipe network, 152 m (500 ft) of 1...

After 50 years the connections between fresh water pipes (800-1000mm diameter) need to be repaired due to aging and dissolution of the filling material. Only in Vienna 3000km of pipes need to be improved, which requires a robotic solution. The main challenge is to accurate place the robot in the center of the pipe while overcoming the push back forces and vibrations caused in the cleaning proce...

I Abstract European cities spend in the order of one billion Euros a year to rehabilitate water supply networks. Rehabilitation costs will increase in the coming decades as networks age and deteriorate. The rational behind today’s rehabilitation decisions is unclear. In the best case, decisions are based on practical experience like failure frequency. During the past 10-20 years, most of the la...

This paper experimentally studies the heat absorption performance of a heat sink with vertical embedded heat pipes in the aluminum blade. The cooling system with embedded heat pipes distributes heat from the CPU to both the base plate and the heat pipes, and then transfer heat from fins to the Environment. The thermal resistance and heat transfer coefficient are evaluated for natural convection...

The detection of bubbles in liquid metals is important for many technical applications. The opaqueness and the high temperature of liquid metals set high demands on the measurement system. The high electrical conductivity of the liquid metal can be exploited for contactless methods based on electromagnetic induction. We will present a measurement system which consists of one excitation coil and...

Nondestructive evaluation of the gas pipeline system is most commonly performed using magnetic flux leakage (MF L) techniques. A major segment of this network employs seamless pipes. The data obtained from MFL inspection of seamless pipes is contaminated by various sources of noise; including seamless pipe noise due to material properties of the pipe, lift -off varia tion of MFL sensor due to m...

The study of two-phase fluid flow behavior in hydraulic structures such as pressurized flow tunnels, culverts, sewer pipes, junctions and other similar conduits is of great importance. A two-phase mixture flowing in a pipe can exhibit several interfacial geometries such as bubbles, slugs or films, depending on the fluid and hydrodynamic properties of flow. The main variables, giving rise to a v...

Aim of this work is to analyze and to synthesize acoustic signals emitted by organ pipes. An Independent Component Analysis technique is applied to study the behavior of single notes or chords obtained in real and simulated environments. These analyses suggest that the pipe acoustic signals can be described by a mixture of nonlinear oscillations obtained by a self-sustained feedback system (i.e...

Flow in a circular pipe fitted with segmental baffles may be treated as a shellwithout-tube system. Its pressure drop has been calculated by adapting the Kern correlation [1] for pressure drop in the shell side of shell-and-tube heat exchangers. The Kern correlation is essentially based on the Hagen – Poiseuille equation for laminar flow, but flow visualization results presented here show that ...