Horizon 1 1 17 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES Geophysical Research Letters 6388-6396 gas-particle mixtures turbulence clustering maximum particle concentration particle Reynolds number 2019 fdi:010076486 ENG Geophysical Research Letters 0094-8276 ISI:000477616300027 12 10.1029/2019gl082658 https://www.documentation.ird.fr/hor/fdi:010076486 https://www.documentation.ird.fr/intranet/publi/2019/08/010076486.pdf 46 Horizon (IRD) The maximum solid phase concentration in geophysical turbulent gas-particle mixtures is essential for understanding the flow dynamics but is poorly known. We present laboratory experiments on turbulent mixtures of air and ceramic particles generated in a vertical pipe. The mixtures had maximum bulk concentrations C-max = 0.7-2.4 vol. % set by the onset of clustering and that increased with the degree of turbulence. Comparison with results of similar experiments with less dense (glass) particles reveals that C-max increases with the particle Reynolds number according to C-max = 0.78 x Re-p(0.17). Published results of experiments at specific Re-p in different configurations are consistent with our data, suggesting that the model for C-max may be generally applicable to turbulent mixtures. From our empirical laws we infer that natural turbulent gas-particle flows with Re-p similar to 10(2)-10(5) have maximum solid concentrations of similar to 2-5 vol. %. 066 ; 064 ; 020 UR163