The motion of the free liquid surface inside a reservoir is called sloshing. Itis of large interest in different industrial fields such as satellite and spacecrafttrajectory control, automotive industry, nuclear engineering, buildingdesign, etc. The framework of propellant management on spacecraft is ofmain interest for this PhD thesis, even if its outcome can be applied to manyother fields concerned by sloshing.Being able to understand the behavior of the fluid in a reservoir subjectedto extreme environmental conditions means being able to predict its positionand topology inside the tank, for a given external and gravitationalacceleration and a determined thermodynamic condition. The predictionand control of this motion is far from being understood due to the differentparameters that play a role in the dynamic system such as the geometryof the container, the type of external excitation (shape, frequency contentand amplitude), the level of the liquid and finally the kind of liquid. In particular,the design of propulsion systems are affected by this phenomenon,still hampered by the unavailability of validated CFD models. Moreover theexisting experimental studies are mainly based on intrusive and local singlepoint measurement techniques, which give no information on the behaviorof the 3D liquid interface and on the velocity field inside the liquid phase.The main goal of this project has been to extend the experimental approachof liquid sloshing investigation in space propulsion, studying, developing andimproving non-intrusive measurement techniques for free surface behaviorand velocity characterization in the liquid phase. In particular, the free surfacebehavior have been studied by means of Laser Detection and Recordingtechnique (LeDaR), retrieving the profile of the interface over a line, andReference Image Topography technique (RIT), capturing the instantaneous3D interface shape. In addition, Particle Image Velocimetry (PIV) have beenused to measure the 2D velocity field in the main section of the reservoir.Tests performed with water were used as simpler test case to perform thetechniques while liquid nitrogen has been used as replacement uid havingphysical properties similar to real space propellants.The experimental problems of the selected measurement techniques relatedto the particular application have been addressed and a solution has beenproposed. Especially, the selection of tracers which could comply with theuse of a cryogenic fluid while for RIT the possibility to deal with circulardomains and to measure the absolute value of the liquid level. Finally, PIV in wavy ows needed to deal with dynamic curved interfaces for whicha widely-accepted processing algorithm was not available in literature andbesides, the choice of the particles and their seeding procedure in cryogenicsfluids had to be solved.Some applications are shown, which present the potentiality of the techniquesfor a new insight on sloshing flows with the future purpose of providingan accurate database for the verification and validation of numericalsimulations and a better understanding of the phenomena. / Doctorat en Sciences de l'ingénieur et technologie / info:eu-repo/semantics/nonPublished

<p> Understanding boundary layer transition is fundamental to hypersonic vehicle design as the significant heating induced by the transition process informs the development of vehicle thermal protection systems. Carbon-based thermal protection systems have been shown to decrease thermal loads and delay transition by absorbing thermal energy during ablative mass transfer into the boundary layer. To better understand this process, a high-repetition rate measurement technique is needed to temporally resolve carbon species concentrations as they propagate through the boundary layer at frequencies where boundary layer instabilities occur. Carbon monoxide is a dominant product from the chemical reactions that take place during the ablation process and is the species of interest considered in this work. A proposed approach is applying carbon monoxide two-photon laser-induced fluorescence (CO TP-LIF) at 100 kHz+ during a simulated ablation experiment where CO is injected into the boundary layer of an axisymmetric slender-body cone model in the Boeing/AFOSR Mach 6 Quiet Tunnel (BAM6QT) at Purdue University. To develop this capability, a custom-built optical parametric oscillator (OPO) was designed and used in conjunction with a burst-mode laser system to achieve narrowband excitation of CO at 100 kHz. The OPO was designed, built, and characterized through measurements of cavity energy efficiency, spectral bandwidth, and beam quality. Initial demonstrations to show the OPO could successfully achieve CO LIF were conducted in a vacuum cell at 10 Hz. The feasibility of performing CO LIF at 100 kHz in the BAM6QT was then assessed on a bench-scale using a burst-mode laser, a high speed camera, and an imaging intensifier. CO number densities in a vacuum cell were related to those that would be expected within the boundary layer of a 3 degree half-angle cone in the BAM6QT, and a series of measurements were made at these representative conditions. Appreciable signal levels were attained for single dimensional focused line measurements demonstrating high potential for using this technique in the BAM6QT at 100 kHz. The potential for a two-dimensional planar measurement was also assessed with decent promise for success for planar laser sheets of small dimensions (2 mm tall or less). Additionally, an initial BAM6QT test entry was carried out to gain experience with experimental setup; lessons learned from this experience are examined and discussed. To date, CO TP-LIF has only been applied up to 1 kHz repetition rates. This work represents a 100 fold increase over the current CO LIF state of the art and the first reported measurements, bench scale or otherwise, of 100 kHz-rate CO LIF. This lays the foundation for future CO LIF experiments in the BAM6QT at kHz-MHz repetition rates. </p>

L'utilisation des techniques de mesure optiques impose un choix, souvent difficile, entre la résolution temporelle et la résolution spatiale. L'interferométrie Speckle (IS) fournit des mesures des champs d'amplitudes de vibration de grande résolution spatiale, mais la résolution temporelle des mesures est réduite par les cadences d'acquisition des détecteurs. La thèse est dédiée au développement d'un système interférométrique adapté à la mesure des vibrations et des phénomènes dynamiques des structures, basé sur les principes de l'IS, mais ayant une résolution temporelle accrue. Le système a été testé à des cadences de plus de 26000 images/s pour les cas suivants : sollicitation harmonique mono-fréquence ou par une forme d'onde arbitraire ; sollicitation dynamique par une séquence d'échelons de force ; choc mécanique. Les essais ont démontré que le système est capable de dépasser les systèmes classiques d'IS à laser continu en ce qui concerne la mesure des phénomènes dynamiques. / The use of optical measurement techniques requires a choice, often difficult, between temporal resolution and spatial resolution. Speckle interferometry (IS) provides high spatial resolution maps of vibration amplitudes, but the temporal resolution of measurements is reduced, due to the low acquisition rates of detectors. The thesis is dedicated to the development of an interferometric system that is able to measure dynamic phenomena with superior temporal resolution. The system was tested at acquisition rates exceeding 26,000 frames/s, for the following cases: harmonic excitation; arbitrary excitation; dynamic loading by a staircase signal and mechanical shock. The tests showed that the system is able to overcome conventional systems of continuous wave SI with respect to the measurement of dynamic phenomena.

<p>Hypersonic flow conditions, such as temperature, pressure, and flow velocity, are challenging to measure on account of the extreme conditions experienced by a craft moving above Mach 5. At Mach 5, the temperature in stratospheric air behind a normal shock wave exceeds temperatures of 1,300 K, and as the craft speed increases, so does the temperature. At these temperatures and conditions, traditional measurement techniques such as thermocouples and pressure transducers either alter the flow path, affecting the measurement, or they do not survive the external conditions. As such, there is interest in investigating alternative ways to measure flow properties. This thesis focuses on the implementation of several optical measurement techniques designed to determine the flow temperature, density gradient, and flow velocity in a detonation driven shock tube. A detonation driven shock tube was chosen for the project as it reliably creates high-speed, low-density, gas flows that are reminiscent of hypersonic conditions. </p><p>The first optical measurement technique implemented was background oriented schlieren, a measurement technique that quantitatively provides density gradient data. Experimental data obtained at pressures up to 3,000 psia resulted in density gradients at the exit of the detonation tube in good agreement with the literature.</p><p>The detonation tube was also fitted with two fiber optic ports to gather chemiluminescence thermometry data. Both a Stellarnet Black-Comet spectrometer and a Sydor Ross 2000 streak camera were used to capture spectroscopic data at these ports, in order to determine the detonation speed and the rotational temperature of the intermediate OH* combustion products. The Stellarnet spectrometer did not have a fast enough data capture rate to gather reliable data. While the streak camera captured data quickly, we had difficulty gathering enough light from the combustion event and the gathered data was very noisy. The streak camera did however capture the time duration of the full combustion event, so if the fiber connector ports are improved this data taking method could be used in the future to gather rotational temperature data. Both measurement techniques provided some unintrusive measurements of high-speed flows, and improvements to the data taking system could provide much needed information on hypersonic flow conditions. </p>