title: Scattering of ultrasonic shock waves in suspensions of silica nanoparticles.
abstract: Experiments are carried out to assess, for the first time, the validity of a generalized Burgers' equation, introduced first by Davidson [J. Acoust. Soc. Am. 54, 1331-1342 (1973)] to compute the nonlinear propagation of finite amplitude acoustical waves in suspensions of "rigid" particles. Silica nanoparticles of two sizes (33 and 69 nm) have been synthesized in a water-ethanol mixture and precisely characterized via electron microscopy. An acoustical beam of high amplitude is generated at 1 MHz inside a water tank, leading to the formation of acoustical shock waves through nonlinear steepening. The signal is then measured after propagation in a cylinder containing either a reference solution or suspensions of nanoparticles. In this way, a "nonlinear attenuation" is obtained and compared to the numerical solution of a generalized Burgers' equation adapted to the case of hydrosols. An excellent agreement (corresponding to an error on the particles size estimation of 3 nm) is achieved in the frequency range from 1 to 40 MHz. Both visco-inertial and thermal scattering are significant in the present case, whereas thermal effects can generally be neglected for most hydrosols. This is due to the value of the specific heat ratio of water-ethanol mixture which significantly differs from unity.
authors.affiliation: Institut des NanoSciences de Paris-UMR CNRS 7588, Université Pierre et Marie Curie-Paris 6, 4 place Jussieu, 75252 Paris Cedex 05, France. michael.baudoin@univ-lille1.fr
authors.forename: Michael
authors.initials: M
authors.lastname: Baudoin
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Thomas
authors.forename: François
authors.initials: F
authors.lastname: Coulouvrat
authors.forename: Corinne
authors.initials: C
authors.lastname: Chanéac
mesh_terms: D003198:Computer Simulation; D000431:Ethanol; D005583:Fourier Analysis; D019220:High-Energy Shock Waves; D053758:Nanoparticles; D017711:Nonlinear Dynamics; D009716:Numerical Analysis, Computer-Assisted; D010316:Particle Size; D015203:Reproducibility of Results; D012542:Scattering, Radiation; D012822:Silicon Dioxide; D013696:Temperature; D013997:Time Factors; D014465:Ultrasonics; D014867:Water
chemical_list: D014867:Water; D000431:Ethanol; D012822:Silicon Dioxide