Aerobreakup in Rarefied Supersonic Gas Flows

Abstract

We present new experimental results on the interfacial instabilities and breakup of Newtonian liquid drops suddenly exposed to rarefied, high-speed (Mach 3) air flows. The experimental approach allows for the first time detailed observation of interfacial phenomena and mixing throughout the breakup cycle over a wide range of Weber numbers. Key findings are that Rayleigh-Taylor instability alone is the active mechanism for freestream Weber numbers as low as 28 for low viscosity liquids and that stripping rather than piercing is the asymptotic regime as We→∞. This and other detailed visual evidence over 26<We<2,600 are uniquely suitable for testing Computational Fluid Dynamics (CFD) simulations on the way to basic understanding of aerobreakup over a broad range of conditions.

Water droplet deformation and breakup in the vicinity of the leading edge of an incoming airfoil

“…Specifically, it covered his personal work [71,92,91,90] and the work of many other researchers. Attending to the mechanism leading to the breakup it was established another classification defining two principal breakup regimes:…”

“…Then, attention was paid to the breakup morphology and a similar classification of breakup mode as the one found in Pilch and Erdman [73] Some comment was made on the work of Theofanous et al [92], and the deviation in the breakup morphology for rarefied, supersonic ambient flows. Dimensionless groups were defined and transitional Weber number between the breakup modes were reviewed for both low and large Ohnesorge numbers.…”

“…Probably one of the most interesting experimental work up to now was the one of Theofanous et al in 2004 [92] because of its discussion. For their experiment, they used the Alpha facility, which was a supersonic wind tunnel especially designed to study the aerobreakup of the viscoelastic fluids.…”

“…Droplet breakup due to strong aerodynamics forces have been widely studied over the last half-century, starting with the works of Lane [56], Hinze [36], Wolfe and Andersen [102], or Ranger and Nicholls [77,78], passing through Krezeczkowski [54], Pilch and Erdman [73], O'Rourke and Amsden [67], Wierzba and Takayama [101], Wierzba [100] or Hsiang and Faeth [40,41] up to the more recent works of Han and Tryggvasson [30,31], Luxford et al [24,60,59], Chen [14], Theofanous et al [92,91], Guildenbecher [29] and Theofanous [90].…”

“…Some of previous mentioned works were numerical approaches such as those of Han and Tryggvasson [30,31], and Chen [14] or only theorize [36] while the rest were experimental approaches. Most of the experimental studies have been conducted in shock-tubes ( [77,101,40,41]), or wind tunnels ( [56,24,60,59,100,54,92,91,90]). …”