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Thermoacoustic instabilities often occur in a combustion chamber of a jet engine when pressure fluctuations from the released heat create a closed feedback loop with the fluctuations of the inlet air velocity, causing further combustion instabilities that enhance the cycle back again. Since most jet engine combustion chambers use liquid fuel dispersed into droplets by an airblast atomizer, any fluctuations occurring in the air entering the airblast nozzle could affect the atomization process of the liquid fuel and the air to fuel ratio distribution inside the combustor. The present experimental study focuses on the influence of the pulsating airflow on the spray characteristics during the airblast atomization process. The experiments were carried out with a two-dimensional prefilmer in which a water film flow was generated on one surface. A siren excited the airflow at approximately 120 Hz. The oscillation of the airflow was characterized by a Constant Temperature Anemometer, while the developed spray was examined using Phase Doppler Anemometry where droplet velocities and the droplet size distribution were measured. By processing the droplet characteristics, an oscillation of the mean diameter, Sauter Mean Diameter and droplet velocity is observed. In comparison to a non-forced flow case as well as theoretical predictions of the SMD based on the air velocity, these results may indicate that the oscillating air velocity causes a timedependent separation of the droplets which results in those fluctuating spray characteristics.

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