Acoustic and streaming velocity components in a resonant waveguide at high acoustic levels.
Rayleigh streaming is a steady flow generated by the interaction between an acoustic wave and a solid wall, generally assumed to be second order in a Mach number expansion. Acoustic streaming is well known in the case of a stationary plane wave at low amplitude: it has a half-wavelength spatial periodicity and the maximum axial streaming velocity is a quadratic function of the acoustic velocity amplitude at antinode. For higher acoustic levels, additional streaming cells have been observed. Results of laser Doppler velocimetry measurements are here compared to direct numerical simulations. The evolution of axial and radial velocity components for both acoustic and streaming velocities is studied from low to high acoustic amplitudes. Two streaming flow regimes are pointed out, the axial streaming dependency on acoustics going from quadratic to linear. The evolution of streaming flow is different for outer cells and for inner cells. Also, the hypothesis of radial streaming velocity being of second order in a Mach number expansion, is not valid at high amplitudes. The change of regime occurs when the radial streaming velocity amplitude becomes larger than the radial acoustic velocity amplitude, high levels being therefore characterized by nonlinear interaction of the different velocity components.
Experimental investigation of non-linearities in thermoacoustic systems: Streaming, transition to turbulence and entrance effects
The pursuit of my PhD has been a life-changing journey and it would not have been completed without the support of many persons and entities. 
First and foremost, I would like to acknowledge my advisors for all the support and guidance they gave me. I am grateful to Dr. Ehab Abdelrahman who has been supportive to my career goals and who worked sincerely to secure the financial and academic support not only for me but also for the whole thermoacoustic research team. Also, I would like to say a very big “thank you” to Dr. Abdelmaged who worked actively to provide me a sincere academic, professional and personnel guidance. I am also grateful to him for the nice “walk and talk” time we spent together discussing both scientific and general-life issues. 
I would like to thank Dr. Ahmed Abdel-Rahman for the fruitful discussions we had at the beginning of my PhD research. I would like to thank my colleagues in the thermoacoustic research team for the time we spent together. Also, I am thankful to my friend Khaled Elbeltagy for the sleepless nights we were working together to catchup on the deadlines of the projects. 
I am grateful to the financial support received towards my PhD from Yousef Jameel PhD fellowship through the American University in Cairo. I am also grateful to the fund received from the Egyptian Academy of Scientific Research and Technology to undertake my PhD. Also, I would like to thank the European union for funding my work . 
I greatly appreciate the support received from the collaborative research conducted with Pprime Institute, Poitiers University. I am especially grateful to Dr. Helene Bailliet for the sincere academic guidance during my stay in France. This collaborative work would not have been possible without the financial support received from both the American University in Cairo and Pprime Institute. 
Last but not least, I would like to thank my family for all their love and support. For my parents who did sacrifice their time and money to raise me with a love of hard working which is the pillar for all my pursuits. Most importantly, I would like to thank my loving, encouraging and patient wife, Alaa, for the faithful support throughout all ups and downs of my PhD journey. Thank you.
Millimeter-Wave Radar Clutter
Backscatter and attenuation theory clutter characteristics detection of targets immersed in clutter.