Sharif Digital Repository

In This project the most important phenomena for design of Vibration Isolation Module is investigated and modeled. These isolators are used in mooring Arrays. One of the most important problems in design of these isolators is lacking of suitable information in resources. Vortex Induced Vibration in Towed Cable and Flutter of Drogue are the most important source of vibrations. They are modeled and frequency band for a typical Sonar Array is calculated. Then by investigating of Normal and Tangantional Vibration in towed cables, it was found that normal vibration is damped, so the Isolators must be damped transactional vibrations. Before final design, for better understanding of the problems... 

In positioning and navigation, Sonar with utilization of sound waves in water environments is similar to the role of Radar in not watered (irrigated) environments. In the Sonar field, modeling and simulation of propagation of sound waves in the undersea environment is a fundamental and very important topic. Nowadays simulation is significant tool that allow to the researchers to predict the quality of Sonar function respect to the experimental conditions. For simulation and modeling of sound wave propagation are used two different methods; Wave theory and Ray theory. In the wave theory, because of the large volume of data, the interpretation of the results is hard. Also in this method cannot... 

One of the methods of measuring the flow rate in a pipe (channel) is by using the acoustic waves with long wavelenghs in Sonar flowmeters. This flowmeter consists of an array of sensors, mounted on the outer wall of the pipe. These sensors by listening and interpreting the sound waves passing through the fluid, would give a “non-intrusive” measurement of the volumetric flow rate. This means that the flowmeter is not in direct contact with the flow and therefore its repair, relocation or replacement will not disturb the flow. In this project, we will provide a clear understanding of the principles and physics involved in sonar-based acoustic flowmeters, by means of numerical simulation of the... 

Measuring flow rate in various industries is an operational challenge that requires to be accurate and fast to avoid wasting energy and money. Various flowmeters are employed in different industries using different principles and methods. Sonar flowmeters are one of the acoustic methods of fluid flow measurement, which do this by listening to the sound of the flow via arrays of sensors. Sonar flow measurement can be achieved by finding either the convection velocity of eddies or the speed of sound in the fluid. The first method is suitable for measuring single-phase flows, which is the subject of this thesis. This method needs a detailed study of turbulence. In the present work, this is...