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Iowa State University

Series

Aerospace Engineering

2017

Articles 1 - 2 of 2

Full-Text Articles in Physics

An Experimental Study On The Characteristics Of Wind-Driven Surface Water Film Flows By Using A Multi-Transducer Ultrasonic Pulse-Echo Technique, Yang Liu, Wen-Li Chen, Leonard J. Bond, Hui Hu Jan 2017

An Experimental Study On The Characteristics Of Wind-Driven Surface Water Film Flows By Using A Multi-Transducer Ultrasonic Pulse-Echo Technique, Yang Liu, Wen-Li Chen, Leonard J. Bond, Hui Hu

Aerospace Engineering Publications

An experimental study was conducted to investigate the characteristics of surface water film flows driven by boundary layer winds over a test plate in order to elucidate the underlying physics pertinent to dynamic water runback processes over ice accreting surfaces of aircraft wings. A multi-transducer ultrasonic pulse-echo (MTUPE) technique was developed and applied to achieve non-intrusive measurements of water film thickness as a function of time and space to quantify the transient behaviors of wind-driven surface water filmflows. The effects of key controlling parameters, including freestream velocity of the airflow and flow rate of the water film, on the dynamics ...


Triaxial-Stress-Induced Homogeneous Hysteresis-Free First-Order Phase Transformations With Stable Intermediate Phases, Valery I. Levitas, Hao Chen, Liming Xiong Jan 2017

Triaxial-Stress-Induced Homogeneous Hysteresis-Free First-Order Phase Transformations With Stable Intermediate Phases, Valery I. Levitas, Hao Chen, Liming Xiong

Aerospace Engineering Publications

Starting with thermodynamic predictions and following with molecular dynamics simulations, special triaxial compression-tension states were found for which the stresses for the instability of the crystal lattice of silicon (Si) are the same for direct and reverse phase transformations (PTs) between semiconducting Si I and metallic Si II phases. This leads to unique homogeneous and hysteresis-free first-order PTs, for which each intermediate crystal lattice along the transformation path is in indifferent thermodynamic equilibrium and can be arrested and studied by fixing the strain in one direction. By approaching these stress states, a traditional two-phase system continuously transforms to homogenous intermediate ...