Fig. 7
From: Characterizing hydrogen-fuelled pulsating combustion on thermodynamic properties of a combustor
Acoustic velocity variation with time and its corresponding frequency spectrum. a–c Time evolution of the instantaneous velocity fluctuations at the midpoint of the combustor and d–f the corresponding frequency spectrum. a, d \(\dot m_{{\mathrm{H}}_2} = 1.0 \times 10^{ - 5}\,{\mathrm{{kg}}}\,{\mathrm{s}}^{ - 1}\), b, e \(\dot m_{{\mathrm{H}}_2} = 5.0 \times 10^{ - 6}\,{\mathrm{{kg}}}\,{\mathrm{s}}^{ - 1}\), c, f \(\dot m_{{\mathrm{H}}_2} = 1.0 \times 10^{ - 6}\,{\mathrm{{kg}}}\,{\mathrm{s}}^{ - 1}\). The dominant and secondary modes are characterized by ω1/2π and ω2/2π in the frequency spectrum, with units of Hz
