Analysis of Droplet Impact Onto Horizontal and Inclined Surfaces

Analysis of Droplet Impact Onto Horizontal and Inclined Surfaces PDF Author: Šefko Šikalo
Publisher:
ISBN: 9783832214661
Category :
Languages : en
Pages : 144

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Analysis of Droplet Impact Onto Horizontal and Inclined Surfaces

Analysis of Droplet Impact Onto Horizontal and Inclined Surfaces PDF Author: Šefko Šikalo
Publisher:
ISBN: 9783832214661
Category :
Languages : en
Pages : 144

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Book Description


The Fluid Dynamics of Droplet Impact on Inclined Surfaces with Application to Forensic Blood Spatter Analysis

The Fluid Dynamics of Droplet Impact on Inclined Surfaces with Application to Forensic Blood Spatter Analysis PDF Author: G. Paul Neitzel
Publisher:
ISBN:
Category : Blood
Languages : en
Pages : 29

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Book Description
"Bloodstain pattern analysis is a technique used in crime-scene reconstruction to determine the point of origin of a blood droplet as well as the method of its creation, e.g., dripping, wiping, or low-to-high-speed impact caused by anything from blunt trauma to cast-off to gunshot wounds. The primary problem of interest in this analysis is to determine of the initial size, speed, and impact angle of a blood droplet that has struck a solid surface through an examination of the bloodstain pattern left on the surface. This research project addressed this problem using a detailed fluid dynamical study of the impact and spreading of a liquid droplet on planar surfaces of variable roughness, wettability, and absorbency oriented at various angles with respect to the velocity vector of the approaching droplet. In particular, this research used a coordinated program of laboratory experiments and numerical simulations to examine the influence of the many parameters associated with such droplet impacts. Given its importance to crime-scene reconstruction, the focus of this work is on how to use the shape of the final stain to determine the initial conditions of droplet impact."--Abstract.

Drop Impact on an Inclined and a Moving Surface

Drop Impact on an Inclined and a Moving Surface PDF Author: Salman Buksh Sookran
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
This thesis has made progress in two different areas related to drop impact onto a surface. Firstly, a systematic experimental study has been performed to understand asymmetric spreading of low and high surface tension liquids on a moving surface. A new time evolution model for droplet spreading on a moving surface was developed. This model regardless the value of surface tension of the liquid can predict the spreading of low viscous (1-4cSt) liquids on a moving surface. Secondly, liquids with viscosity (1-5cSt) and surface tension (17.4-72.8mNm) were used to study the drop impact on moving and inclined surface. Experiments performed with similar normal (0.9-2.9m/s) and tangential (0.8-2.9m/s) velocities on both surfaces to test our hypothesis that spreading/splashing for these two surface conditions should be same. Results indicates that our hypothesis is true, except for some special conditions when, normal and tangential velocities are greater than the range of our analysis.

Collision Phenomena in Liquids and Solids

Collision Phenomena in Liquids and Solids PDF Author: Alexander L. Yarin
Publisher: Cambridge University Press
ISBN: 1107147905
Category : Science
Languages : en
Pages : 629

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Book Description
A unique and in-depth discussion uncovering the unifying features of collision phenomena in liquids and solids, along with applications.

Surface Science Techniques

Surface Science Techniques PDF Author: Gianangelo Bracco
Publisher: Springer Science & Business Media
ISBN: 3642342434
Category : Science
Languages : en
Pages : 668

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Book Description
The book describes the experimental techniques employed to study surfaces and interfaces. The emphasis is on the experimental method. Therefore all chapters start with an introduction of the scientific problem, the theory necessary to understand how the technique works and how to understand the results. Descriptions of real experimental setups, experimental results at different systems are given to show both the strength and the limits of the technique. In a final part the new developments and possible extensions of the techniques are presented. The included techniques provide microscopic as well as macroscopic information. They cover most of the techniques used in surface science.

Moving Particle Semi-implicit Method

Moving Particle Semi-implicit Method PDF Author: Seiichi Koshizuka
Publisher: Academic Press
ISBN: 0128128372
Category : Science
Languages : en
Pages : 307

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Book Description
Moving Particle Semi-implicit Method: A Meshfree Particle Method for Fluid Dynamics begins by familiarizing the reader with basic theory that supports their journey through sections on advanced MPH methods. The unique insights that this method provides include fluid-structure interaction, non-Newtonian flow, and cavitation, making it relevant to a wide range of applications in the mechanical, structural, and nuclear industries, and in bioengineering. Co-authored by the originator of the MPS method, this book is the most authoritative guide available. It will be of great value to students, academics and researchers in industry. - Presents the differences between MPH and SPH, helping readers choose between methods for different purposes - Provides pieces of computer code that readers can use in their own simulations - Includes the full, extended algorithms - Explores the use of MPS in a range of industries and applications, including practical advice

High Performance Computing in Science and Engineering ́16

High Performance Computing in Science and Engineering ́16 PDF Author: Wolfgang E. Nagel
Publisher: Springer
ISBN: 3319470663
Category : Computers
Languages : en
Pages : 666

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Book Description
This book presents the state-of-the-art in supercomputer simulation. It includes the latest findings from leading researchers using systems from the High Performance Computing Center Stuttgart (HLRS) in 2016. The reports cover all fields of computational science and engineering ranging from CFD to computational physics and from chemistry to computer science with a special emphasis on industrially relevant applications. Presenting findings of one of Europe’s leading systems, this volume covers a wide variety of applications that deliver a high level of sustained performance. The book covers the main methods in high-performance computing. Its outstanding results in achieving the best performance for production codes are of particular interest for both scientists and engineers. The book comes with a wealth of color illustrations and tables of results.

Ice Adhesion

Ice Adhesion PDF Author: K. L. Mittal
Publisher: John Wiley & Sons
ISBN: 1119640377
Category : Technology & Engineering
Languages : en
Pages : 704

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Book Description
This unique book presents ways to mitigate the disastrous effects of snow/ice accumulation and discusses the mechanisms of new coatings deicing technologies. The strategies currently used to combat ice accumulation problems involve chemical, mechanical or electrical approaches. These are expensive and labor intensive, and the use of chemicals raises serious environmental concerns. The availability of truly icephobic surfaces or coatings will be a big boon in preventing the devastating effects of ice accumulation. Currently, there is tremendous interest in harnessing nanotechnology in rendering surfaces icephobic or in devising icephobic surface materials and coatings, and all signals indicate that such interest will continue unabated in the future. As the key issue regarding icephobic materials or coatings is their durability, much effort is being spent in developing surface materials or coatings which can be effective over a long period. With the tremendous activity in this arena, there is strong hope that in the not too distant future, durable surface materials or coatings will come to fruition. This book contains 20 chapters by subject matter experts and is divided into three parts— Part 1: Fundamentals of Ice Formation and Characterization; Part 2: Ice Adhesion and Its Measurement; and Part 3: Methods to Mitigate Ice Adhesion. The topics covered include: factors influencing the formation, adhesion and friction of ice; ice nucleation on solid surfaces; physics of ice nucleation and growth on a surface; condensation frosting; defrosting properties of structured surfaces; relationship between surface free energy and ice adhesion to surfaces; metrology of ice adhesion; test methods for quantifying ice adhesion strength to surfaces; interlaboratory studies of ice adhesion strength; mechanisms of surface icing and deicing technologies; icephobicities of superhydrophobic surfaces; anti-icing using microstructured surfaces; icephobic surfaces: features and challenges; bio-inspired anti-icing surface materials; durability of anti-icing coatings; durability of icephobic coatings; bio-inspired icephobic coatings; protection from ice accretion on aircraft; and numerical modeling and its application to inflight icing.

Heat transfer in data centers, volume II

Heat transfer in data centers, volume II PDF Author: Chengbin Zhang
Publisher: Frontiers Media SA
ISBN: 2832507484
Category : Technology & Engineering
Languages : en
Pages : 89

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Book Description


Experimental Investigation of Droplet Impact Dynamics on Solid Surfaces

Experimental Investigation of Droplet Impact Dynamics on Solid Surfaces PDF Author: Kalpak Prakash Gatne
Publisher:
ISBN:
Category :
Languages : en
Pages : 105

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Book Description
A study of the normal impact of liquid droplets on a dry horizontal substrate is presented in this thesis. The impact dynamics, spreading and recoil behavior are captured using a high-speed digital video camera at 2000 frames per second. A digital image processing software was used to determine the drop spread and height of the liquid on the surface from each frame. To ascertain the effects of liquid viscosity and surface tension, experiments were conducted with four pure liquids (water, ethanol, propylene glycol and glycerin) that have vastly different fluid properties. Three different Weber numbers (20, 40, and 80) were considered by altering the height from which the drop is released. To understand the influence of drop size, experiments were performed in which the drop size was varied for the same fluid. Also, the effect of substrate material was studied by comparing the impact on two different substrates: glass (hydrophilic) and PTFE or Teflon (hydrophobic). The high-speed photographs of impact, spreading and recoil are shown and the temporal variations of dimensionless drop spread and height are provided in the paper. Experiments were performed to study the influence of addition of surface active agents or surfactants in aqueous solution on the droplet impact phenomenon. Three surfactants were used with varying diffusion rates: SDS (anionic), CTAB (cationic) and Triton x 100 (non ionic). The spreading and recoil of the drops of surfactant solutions is studied at concentrations of half the critical micelle concentration (CMC) and twice CMC. To underscore the dynamic effects, comparative experiments for the three surfactants were performed so that all the solutions had the same value of equilibrium surface tension. The role played by impact velocity in the collision of surfactant laden drops was studied by comparing the results for two different impact velocities. The influence of surfactant concentration was studied by performing experiments varying the surfactant concentrations. The results show that changes in liquid viscosity, surface tension, and surfactant concentration significantly affect the spreading and recoil behavior. In the case of pure liquids, for a fixed Weber number, lower surface tension promotes greater spreading and higher viscosity dampens spreading and recoil. Using a simple scale analysis of energy balance, it was found that the maximum spread factor varies as Re 1/5when liquid viscosity is high and viscous effects govern the spreading behavior. The drop size had no binding when the Weber number was maintained constant and the Reynolds numbers were comparable. The nature of the substrate plays a very important role. Impact on hydrophobic substrates can result in dramatic recoils and rebound. For aqueous solutions with surface active agents, it was observed that higher diffusion rate surfactants result in higher spreading factors and weaker oscillations. The spreading and recoil behavior can be correlated to the dynamic surface tension response of the surfactant solutions. With increase in impact velocity, the gain in spreading factor over a pure water drop decreases. Also, lowering of the surfactant concentration results in lower spreading factor and stronger recoil - a behavior closer to that of pure water.