Tammisola, OO and Sasaki A, and Lundell, F and Matsubara, M and Soderberg, LD *Stabilizing effect of surrounding gas flow on a plane liquid sheet.* Journal of Fluid Mechanics, 672. pp. 5-32. (Unpublished)

## Abstract

The stability of a plane liquid sheet is studied experimentally and theoretically, with an emphasis on the eﬀect of the surrounding gas. Co-blowing with a gas velocity of the same order of magnitude as the liquid velocity is studied, in order to quantify its eﬀect on the stability of the sheet. Experimental results are obtained for a water sheet in air at Reynolds number Rel = 3000 and Weber number W e = 300, based on the half-thickness of the sheet at the inlet, water mean velocity at the inlet, the surface tension between water and air and water density and viscosity. The sheet is excited with diﬀerent frequencies at the inlet and the growth of the waves in the streamwise direction is measured. The growth rate curves of the disturbances for all air ﬂow velocities under study are found to be within 20 % of the values obtained from a local spatial stability analysis, where water and air viscosities are taken into account, while previous results from literature assuming inviscid air overpredict the most unstable wavelength with a factor 3 and the growth rate with a factor 2. The eﬀect of the air ﬂow on the stability of the sheet is scrutinized numerically and it is concluded that the predicted disturbance growth scales with (i) the absolute velocity diﬀerence between water and air (inviscid eﬀect) and (ii) the square root of the shear from air on the water surface (viscous eﬀect).

Item Type: | Article |
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Subjects: | UNSPECIFIED |

Divisions: | Div A > Energy |

Depositing User: | Cron Job |

Date Deposited: | 18 May 2016 17:42 |

Last Modified: | 23 May 2016 07:02 |

DOI: |