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Full-Text Articles in Engineering

Jet Noise Reduction: A Fresh Start, Christopher K. Tam, Fang Q. Hu Jan 2023

Jet Noise Reduction: A Fresh Start, Christopher K. Tam, Fang Q. Hu

Mathematics & Statistics Faculty Publications

Attempts to reduce jet noise began some 70 years ago. In the literature, there have been many publications written on this topic. By now, it is common knowledge that jet noise consists of a number of components. They possess different spectral and radiation characteristics and are generated by different mechanisms. It appears then that one may aim at the suppression of the noise of a single component instead of trying to reduce jet noise overall. The objective of the present project is to reduce large turbulence structures noise. It is the most dominant noise component radiating in the downstream direction. …


Numerical Study On The Dynamic Process Of Single Plume Flow In Thermal Convection With Polymers, Jian-Ping Cheng, Wei-Hua Cai, Hong-Na Zhang, Feng-Chen Li, Lian Shen, Shi-Zhi Qian Jan 2019

Numerical Study On The Dynamic Process Of Single Plume Flow In Thermal Convection With Polymers, Jian-Ping Cheng, Wei-Hua Cai, Hong-Na Zhang, Feng-Chen Li, Lian Shen, Shi-Zhi Qian

Mechanical & Aerospace Engineering Faculty Publications

A direct numerical simulation of single plume flow in thermal convection with polymers was carried out in a domain with 1:3 as the width to height ratio. The heat transport ability is weakened by adding polymers within the here-investigated governing parameter range. However, it is promoted when the maximum polymer extension L is increased. The distribution of vertical velocity and temperature indicates that the plume in the polymer solution case is speeded up and widens bigger as compared to that in the Newtonian fluid case. Inside the plume, polymer chains tend to release energy at the position where the …


Radial And Longitudinal Motion Of The Arterial Wall: Their Relation To Pulsatile Pressure And Flow In The Artery, Dan Wang, Linda Vahala, Zhili Hao Jan 2018

Radial And Longitudinal Motion Of The Arterial Wall: Their Relation To Pulsatile Pressure And Flow In The Artery, Dan Wang, Linda Vahala, Zhili Hao

Mechanical & Aerospace Engineering Faculty Publications

The aim of this paper is to analyze the radial and longitudinal motion of the arterial wall in the context of pulsatile pressure and flow, and to understand their physiological implications for the cardiovascular system. A reexamination of the well-established one-dimensional governing equations for axial blood flow in the artery and the constitutive equation for the radial dilation of the arterial wall shows that two waves—a pulsatile pressure wave in the artery and a radial displacement wave in the arterial wall—propagate simultaneously along the arterial tree with the same propagation velocity, explaining why this velocity combines the physical properties and …


Dynamic Unstructured Method For Prescribed And Aerodynamically Determined Relative Moving Boundary Problems, Kamakhya Prasad Singh Jul 1995

Dynamic Unstructured Method For Prescribed And Aerodynamically Determined Relative Moving Boundary Problems, Kamakhya Prasad Singh

Mechanical & Aerospace Engineering Theses & Dissertations

A new methodology is developed to simulate unsteady flows about prescribed and aerodynamically determined moving boundary problems. The method couples the fluid dynamics and rigid-body dynamics equations to capture the time-dependent interference between stationary and moving boundaries. The unsteady, compressible, inviscid (Euler) equations are solved on dynamic, unstructured grids by an explicit, finite-volume, upwind method. For efficiency, the grid adaptation is performed within a window around the moving object. The Eulerian equations of the rigid-body dynamics are solved by a Runge-Kutta method in a non-inertial frame of reference. The two-dimensional flow solver is validated by computing the flow past a …


An Adaptive Remeshing Finite Element Method For High-Speed Compressible Flows Using Quadrilateral And Triangular Elements, Gururaja R. Vemaganti Apr 1989

An Adaptive Remeshing Finite Element Method For High-Speed Compressible Flows Using Quadrilateral And Triangular Elements, Gururaja R. Vemaganti

Mechanical & Aerospace Engineering Theses & Dissertations

In this study a new adaptive remeshing method for high speed compressible flow analysis is presented. The method uses quadrilateral elements where possible, and triangles are introduced as needed. The primary goal of this study is to develop a remeshing method which uses both the concepts of unstructured and structured meshes for the finite element analysis to predict accurate aerodynamic heating in problems related to high speed viscous flows. The remeshing method uses a solution based on an old mesh to create a new mesh based on an advancing front technique. In the present implementation, a structured mesh of quadrilaterals …