Abstract

Conventional methods of classifying droplet breakup are evaluated in the context of unique variation in environmental and droplet fluid conditions. Most characterization is developed for subsonic speeds and Newtonian fluids, so this study extends understanding on how these forms change to a span of applications outside these conditions. Presented examples include the impact effects on hypersonic vehicles travelling through precipitation, where even smallest of rain drops at such speeds can cause damage. Before the droplet even reaches the vehicle, it interacts with the detached bow shock that leads it. Another example of exceptional recent concern is risk of viral transmission by breakup function within human saliva in sneezes, coughs and speaking. Such biofluid behavior is complicated by viscous and elastic properties, subject to molecular composition that varies person to person by function of their age, gender, and medical conditions. Both phenomena are difficult to image on the scale of internal droplet fluid flow and droplets of aerosolizing diameters. Thus, this study uses a multi-stage model that couples full scale simulations to simulations of a droplet scale. This multi-scale modelling approach develops a low cost computational method for system evaluation. The hypersonic impact model explores droplet breakup physics that resolve shock transmission through the droplet, with analysis of breakup driving factors of evaporation and cavitation. Similar studies are examined for the viscoelastic breakup of ejected saliva. The results indicate neither example can use conventional methods to characterize the droplet breakup seen. Droplets interacting with a shock experience internal fluid dynamics that present before the expected breakup form. Droplets of viscoelastic nature do not reach the expected breakup form, instead snapping back to prior shape. The results indicate that further experimental and simulation work is needed to address these unique conditions.

Notes

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Graduation Date

2021

Semester

Summer

Advisor

Kinzel, Michael

Degree

Master of Science in Aerospace Engineering (M.S.A.E.)

College

College of Engineering and Computer Science

Department

Mechanical and Aerospace Engineering

Degree Program

Aerospace Engineering; Thermofluid Aerodynamic Systems

Format

application/pdf

Identifier

CFE0008610;DP0025341

URL

https://purls.library.ucf.edu/go/DP0025341

Language

English

Release Date

August 2021

Length of Campus-only Access

None

Access Status

Masters Thesis (Open Access)

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