For the experimental conditions of sound pressure levels at nodes I sub p between 160 to 166 db and resonance frequencies (f) between 680 to 2740 Hz in a resonance tube, the initiation of shock waves were found at I sub p 160 db, and the shock waves occurred within + or - 20 Hz in the vicinity of f. In the presence of aerosols with the diameters d sub p of 0.2 to 1.0 sigma m, it was found that acoustically induced shock waves would enhance the rate of aerosol agglomeration. In addition to agglomerating aerosols, shock waves were able to drift aerosols towards nodes which would increase the local aerosol concentration at nodes and thus augmented the degree of agglomeration in an indirect way. An attempt was made to calculate the magnitude of drift velocity due to shock waves as a function of I sub p, f and d sub p. Time required for aerosols to drift from loop to node were computed for several cases and were in qualitative agreement with experimental observations.
NASA STI/Recon Technical Report N
- Pub Date:
- Shock Waves;
- Sound Waves;
- Drift Rate;
- Nodes (Standing Waves);
- Fluid Mechanics and Heat Transfer