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Modélisation Des Signatures Radar Des Tourbillons De Sillage Par Temps De Pluie

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Modélisation Des Signatures Radar Des Tourbillons De Sillage Par Temps De Pluie 5)µ4& &OWVFEFMPCUFOUJPOEV %0$503"5%&-6/*7&34*5²%&506-064& %ÏMJWSÏQBS Institut Supérieur de l’Aéronautique et de l’Espace (ISAE) 1SÏTFOUÏFFUTPVUFOVFQBS Zhongxun LIU le lundi 27 mai 2013 5JUSF Modélisation des signatures radar des tourbillons de sillage par temps de pluie ²DPMF EPDUPSBMF et discipline ou spécialité ED AA : Dynamique des fluides & Signal, image, acoustique et optimisation 6OJUÏEFSFDIFSDIF Équipe d'accueil ISAE-ONERA SCANR %JSFDUFVS T EFʾÒTF M. François VINCENT (directeur de thèse) M. Nicolas JEANNIN (co-directeur de thèse) Jury : François VINCENT, Enseignant-Chercheur ISAE - Directeur de thèse Nicolas JEANNIN, Ingénieur ONERA - Co-directeur de thèse Danielle VANHOENACKER-JANVIER, Professeur UC Louvain - Rapporteur François LE CHEVALIER, Professeur TU Delft - Rapporteur Frédéric BARBARESCO, Ingénieur Thalès Air Systems - Examinateur Vincent BRION, Ingénieur ONERA - Examinateur Abstract In recent years, wake vortex monitoring in real time has emerged as one of the key challenges in air traffic control at landing or taking-off. In clear air, several experimental tests have demonstrated that Lidar is an effective sensor for wake vortex monitoring. In rainy weather, Lidar becomes blind and Radar is a candidate sensor to detect the motion of raindrops in wake vortices. Thus, investigation on radar monitoring of wake vortices in rainy weather is of both scientific and practical interests. This topic has been tackled through three successive steps during this thesis. Firstly, the motion of raindrops in wake vortices has been modeled and simulated. The equation of the motion has been derived and the methodology to compute the raindrops' trajectory and distribution in the flow induced by the wake vortices has been proposed. Secondly, two simulators have been developed for evaluating the radar signa- tures of raindrops in wake vortices. One simulator is based on the simulation of radar signal time series, by superimposing the radar backscattered signal from each raindrop in the wake vortex region. The other one is based on the raindrops' number concentration and velocity distribution in wake vortices, enabling the computation of radar signatures much more efficiently. Those simulators have been used to re- produce experimental configurations and the comparison between measured and simulated signature has shown an interesting agreement at X and W band. Lastly, the interpretation of radar signatures of raindrops in wake vortices has been presented. Based on the computation of three spectral moments, the depen- dence of radar signatures on rain rate, vortex circulation and radar parameters has been studied for vortices generated by different aircraft types. A wake vortex detec- tion method based on the analysis of Doppler spectrum width of raindrops has been proposed. Considering radar scanning under flight path, a methodology to estimate the wake vortex characteristics has been proposed. Preliminary simulation results i ii have shown its effectiveness. The radar signatures of wake vortices in rainy weather have been modeled and analyzed in this thesis. The simulation results have demonstrated the capability of radar to detect wake vortex in rainy weather. The methodologies developed in this thesis can be further exploited for designing new wake vortex radar systems. Key words: Wake vortex, radar, rain, Doppler spectrum, detection R´esum´e Ces derni`eresann´ees,la d´etectiondes turbulences de sillage est apparue comme ´etant un des enjeux les plus importants pour l'am´elioration des proc´eduresde contr^olea´erien,et plus particuli`erement au d´ecollageet `al'atterrissage. Par beau temps, plusieurs exp´erimentations ont montr´eque le LIDAR ´etaitun capteur efficace pour ce type d'application. En pr´esencede pluie ou de nuages, le LIDAR ne peut plus op´ererdu fait de la perte de visibilit´eet le radar devient un capteur int´eressant pour d´etecter le mouvement des gouttes d'eau dans les turbulences de sillage. D`es lors, la surveillance des turbulences de sillage par radar en temps de pluie pr´esente un int´er^et`ala fois pratique et scientifique. Cette th´ematiquea ´et´etrait´ee`atravers trois ´etapes successives. Tout d'abord, le mouvement et la distribution des gouttes d'eau dans les vortex ont ´et´emod´elis´eset simul´es.A partir de l'´equationde la dynamique appliqu´eesur une goutte d'eau, une m´ethode de calcul de la trajectoire des gouttes d'eau et de leur concentration dans les turbulences de sillage a ´et´epropos´ee. Ensuite, deux simulateurs de r´eponse radar des gouttes d'eau dans et autour des vortex ont ´et´epropos´es. Le premier simulateur vise `ag´en´ererdes s´eriestem- porelles de signal radar, simulant la r´eponse individuelle de chaque goutte, pour le d´eveloppement des chaines de traitement radar. Le second simulateur vise `ag´en´erer directement la r´eponse radar id´ealis´ee`apartir de la concentration et de la vitesse des gouttes dans l'´ecoulement provoqu´epar les vortex, ce qui est algorithmiquement plus efficace. Ces deux simulateurs ont ´et´eutilis´espour reproduire des configura- tions exp´erimentales, et une comparaison pr´eliminaireavec les mesures a montr´e une concordance int´eressante entre mesures et simulations en bande X et W. Enfin, l'interpr´etationde la signature radar des gouttes de pluie dans les vortex a ´et´epr´esent´ee. Consid´erant le calcul de trois moments spectraux, la d´ependance de la signature envers diff´erents param`etres,`asavoir l'intensit´ede pr´ecipitation,la circulation des vortex et les param`etresradar, a ´et´e´etudi´eepour des turbulences iii iv de sillage g´en´er´eespar diff´erents types d'avions. Une m´ethode de d´etectiondes turbulences de sillage bas´eesur la largeur du spectre Doppler des gouttes de pluie a ´et´epropos´ee. Consid´erant un radar balayant sous les trajectoires d'approche, un algorithme permettant d'estimer les caract´eristiquesdes turbulences de sillage est propos´e. Des simulations pr´eliminairesont montr´eson efficacit´e. La signature radar des turbulences de sillage par temps de pluie a ´et´emod´elis´ee et analys´eedans cette th`ese.Les r´esultatsde simulations ont d´emontr´eles capacit´es du radar pour la d´etection de ces turbulences. Les m´ethodes d´evelopp´eesdans cette th`esepourront ^etreutilis´eespour le dimensionnement de syst`emesradar d´edi´es`ala surveillance des turbulences de sillage par temps de pluie. Mots cl´es: Tourbillons de sillage, wake vortex, radar, pluie, spectre Doppler, d´etection Acknowledgement I was very excited and moved when I finished the draft version of this manuscript. During this fulfilling and meaningful period of PhD study, I have experienced a lot and a large number of people in France and China are sincerely appreciated. I would like to express my deepest gratitude to Professor Francois Vincent from ISAE and Dr. Nicolas Jeannin from ONERA, for their helpful joint supervision of this PhD work and unconditional support all along the way. The investigation into a multi-disciplinary subject was not very easy, but their generosity and encouragement helped me to overcome all the obstacles. This manuscript would not have been possible without their constructive corrections and comments. I wish to specially thank Mr. Florent Christophe, the director of DEMR in ONERA Toulouse center, for his helpful supervision of my PhD progress. He accepted my PhD application in France, proposed this interesting PhD subject and also supported my PhD study all along the way. The discussions with him on the PhD progress meetings inspired me a lot. I would like to express my great gratitude to Mr. Fr´ed´ericBarbaresco from THALES Air System for his helpful supervision of my six months' training in TRT (Thales Research & Technology). It was his publications on wake vortex that mostly attracted my motivation to choose France as the destination of my PhD study. Professor Michel Bousquet from ISAE is also specially thanked for his sending me the invitation letter and support of my stay at Toulouse. Appreciation must also go to my colleagues in ISAE-DEOS and ONERA-DEMR for their kind hearted help during my stay there. I wish to specially thank Professor Xuesong Wang from NUDT in China, who has supervised my study since I was an undergraduate student and guided me to carry out research work on wake vortex as a PhD student in NUDT since 2008. His everlasting support, encouragement and supervision was a great source of my interest and progress on wake vortex study. Sincere thanks must also go to Dr. Tao Wang from NUDT in China for his valuable suggestions on my PhD work. He v vi has always been willing to help me whenever I needed it. Prof. Shunping Xiao, Prof. Wei Wang, Dr. Dahai Dai, Dr. Jianbing Li, Dr. Jun Li, Dr. Longhai Qu, Dr. Junkai Liu and some other colleagues from NUDT are also thanked for their unconditional help and sharing their knowledge on radar and wake vortex. Very special thanks to my friends who I met with in France. I have benefitted a lot from this life enriching and unforgettable three years and half with them in France. Very special thanks to my friends in China. Their greetings and encourage- ment have always been appreciated. My deepest gratitude goes to my parents and parents in law. My study and life in France would not have been so easy without their understanding and support. I wish to express my deepest love to my dear wife, Jing Xu. Her immeasurable support and endless love encourages me to meet with various challenges. Last but not least, I wish to express my appreciation of this multi-disciplinary PhD subject, which has brought me a broad view of the scientific research activities, including wake vortex aerodynamics, radar, precipitation, information geometry, spiral geometry of wake vortex, the interaction between particle and turbulent flow, etc.
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