This Doctoral dissertation has been focused to study the unsteady aerodynamic loads on bluff bodies.To this aim the following points have been identified and analyzed:Characterization of the flow measured with different types of Pitot tubes and hot wire anemometer at unsteady flow conditions generated by a gust wind tunnel. Design and integrating of the experimental setups required to measure the internal and external wind loads acting on bluff bodies at gusty wind flow conditions. Implementation of semi-empirical mathematical models based on potential flow and relevant phenomenological theories to simulate the experimental results. At various gusty flow conditions, extracting and analyzing the influence of parameters obtained from the developed theoretical models. Empirical estimations are proposed to find out suitable values of the influencing parameters, by fitting the experimental and theoretically predicted results. The experimental setups are performed in an open circuit, closed test section, low speed wind tunnel, with a new sinusoidal gust generator mechanism concept, designed and built at the
This work contains an acceptable solution to the most practical interest to reduce the internal pressure load variations acting on closed envelops (i.e., inner building walls, fairing of rocket, and missile payloads) under gusty wind conditions. To simulate the gusty wind conditions (i.e., tangential unsteady flow condition), an experimental setup of a wind tunnel with a sinusoidal gust generating mechanism has been established in IDR of the Universidad Politécnica de Madrid (IDR/UPM), Spain. The wind tunnel has been equipped with an air reservoir with vent holes. The pressure jumps shown across the vent holes are studied as a function of sinusoidal gust frequency, volume of the air reservoir, and vent hole size. A theoretical model (based on the mass conservation equation and polytropic law gas evolution) has been proposed to predict the pressure jumps and variations under gusty wind conditions. At the end of the work, theoretical and experimental results have been studied and compared. The relationship between pressure loss coefficient
ξ
and flow coefficient
α
under unsteady flow conditions has been evaluated.
In space missions, satellite launchings and missiles for army applications, solid rocket motors plays a major role. As we know that the thrust produced by the rocket engines only gives the forward motion to the rocket body and its payload. The rockets which used Solid fuel, which contain fuel and oxidizer itself called Solid rocket motor. Solid fuel can be prepared by Composite material powders with various combinations. Each combination contains its own parameters and thrust/weight ratios. Depends upon the requirements of the thrust to lift off the mass of the rocket, specific combinations of the chemicals are used in the preparation of the solid propellant grains. To understand the characteristics of various combinations of the propellants, the present work is mainly focused on testing of solid rocket motor thrust generation under various combinations of composite propellants and burning rates of the same. Small scale experimental testing and the results of positive and negative obtained in more than one test will be discussed and solutions will be provided for the obtained negative results.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.