Raindrop Breakup in the Shock Layer of a High-speed Vehicle

Abstract

The problem of predicting raindrop breakup effects in the shock layer of a high-speed vehicle is discussed. Relevant experimental data, obtained in a shock tube with shadowgraph and x-ray photography, are presented in the form of correlations of the nondimensional time to breakup with the Weber number, together with the drop mass variation and trajectory as a function of nondimensional time. The relationship between the experimental situation and the flight case is delineated for the stagnation and downstream conical-flow regions of a high-speed shock layer. Based on the experimental correlations, calculations are made of the impacting drop mass fractions, velocities, and impact angles for a vehicle traversing a rainstorm.

On the physics of aerobreakup

“…We frame this discussion in terms of questions-one of them was posed by one of the referees; the others naturally arose in a detailed consideration of past work, especially of some little-known reports of works summarized by Waldman et al 13 Why was multiwave piercing, which is readily discerned in shadowgraphs, not found in previous experiments? Past work was conducted at atmospheric pressure, so that the required range of We for RTP could only be accessed in a subsonic flow.…”

“…Waldman 26 (summarized but with omission of significant details by Waldman et al 13 ) and of Simpkins The corresponding We for these tests were 10 6 , 2.5 ϫ 10 5 , and 8 ϫ 10 4 , respectively, and the "early," "intermediate," and "late" timings of the catastrophic event correspond to T values of 1.5, 1.7, and 2.6 ͑21, 50, and 145 s͒, respec- tively. The suggestion, as noted already, found experimental ͑based on shadowgraphs͒ and theoretical support from Simpkins and Bales 12 and Harper et al, 11 respectively, which were both published in the same time frame.…”

“…In the discussion ͑Sec. IV͒, we elaborate on the experimental work of Simpkins and Bales 12 and that of Waldman et al, 13 which were carried out at conditions that reached shock Mach numbers of 11, and make the case for an experimental revisit.…”

Empirical Analysis Research on Waterdrop's Deformation by Shock Wave

“…발표된 Adler and Mihora [1] 의 해석 기법에서는 물방 울의 변형 계산을 위해 Ranger and Nicholls 때문에 정확한 물방울의 형상을 관측하기 어렵다 [7] . [8] 가 도출한 경험적 모 델을 Wierzba and Takayama [7] 의 실험 결과에 맞게 아 래와 같이 수정하여 적용하였다. 나기 때문이다 [8,9] .…”

Water Drop/Bow Shock Interactions.

“…The time it takes a droplet to completely lose its mass via stripping is given by equatIons (2) and (6) .…”