Tag: Fluid Dynamics

Effectiveness of Cloth Masks Depends on Type of Covering

sarah JonasResearch Results

Months into the COVID-19 pandemic, wearing a mask while out in public has become the recommended practice. However, many still question the effectiveness of this. To allay doubts, Padmanabha Prasanna Simha, from the Indian Space Research Organisation, and Prasanna Simha Mohan Rao, from the Sri Jayadeva Institute of Cardiovascular Sciences and Research, experimentally visualized the flow fields of coughs under various common mouth covering scenarios. They present their findings in the journal Physics of Fluids.

Using A Public Restroom? Mask Up!

sarah JonasResearch Results

Think you don’t need to worry about COVID-19 while using a public restroom? Researchers from Yangzhou University in China recently reported that flushing public restroom toilets can release clouds of virus-laden aerosols for you to potentially inhale. If that’s not cringeworthy enough, after running additional computer simulations, they’ve concluded that flushing urinals does likewise. In Physics of Fluids, the group shares its work simulating and tracking virus-laden particle movements when urinals are flushed.

Humid Air Can Extend Lifetime of Virus-Laden Aerosol Droplets

sarah JonasResearch Results

The novel coronavirus that causes COVID-19 is thought to spread through natural respiratory activities, but little is known about how the virus is transported through the air. Scientists report in Physics of Fluids on a study of how airflow and fluid flow affect exhaled droplets that can contain the virus. Their model includes a more accurate description of air turbulence that affects an exhaled droplet’s trajectory. Calculations with their model reveal, among other things, an important and surprising effect of humid air.

Masks, PPE Materials Should Be Hydrophilic

sarah JonasResearch Results

Since the COVID-19 virus spreads through respiratory droplets, researchers in India set out to explore how droplets deposited on face masks or frequently touched surfaces dry. Droplets can be expelled via the mouth or nose and studies have shown a substantially reduced chance of infection once they dry. In Physics of Fluids, the researchers publish their findings that surface wetting properties to reduce the drying time of droplets could help lessen the risk of infection from coronaviruses.

Using Physics to Improve Root Canal Efficiency

sarah JonasResearch Results

In Physics of Fluids, scientists report calculations with a model of a conical-shaped root canal inside a tooth. A crucial step in this common dental procedure is irrigation, or rinsing, of the root canal cavity with an antibacterial solution, and the researchers used computational fluid dynamics to determine the effect of temperature on the cleaning efficiency: Higher temperatures can, to a point, improve cleansing, but this benefit falls off if the temperature gets too high.

Droplet Spread from Humans Doesn’t Always Follow Airflow

sarah JonasResearch Results

If aerosol transmission of COVID-19 is confirmed to be significant, as suspected, we will need to reconsider guidelines on social distancing, ventilation systems and shared spaces. Researchers in the U.K. believe a better understanding of different droplet behaviors and their different dispersion mechanisms is also needed. In Physics of Fluids, the group presents a model that demarcates differently sized droplets. This has implications for understanding the spread of airborne diseases, because the dispersion tests revealed the absence of intermediate-sized droplets.

Respiratory Droplet Motion, Evaporation and Spread of COVID-19-Type Pandemics

sarah JonasResearch Results

It is well established the COVID-19 virus is transmitted via respiratory droplets. Consequently, much research targets better understanding droplet motion and evaporation. In Physics of Fluids, researchers developed a mathematical model for the early phases of a COVID-19-like pandemic using the aerodynamics and evaporation characteristics of respiratory droplets. The researchers modeled the pandemic dynamics with a reaction mechanism and then compared the droplet cloud ejected by an infected person versus one by a healthy person.

Bubble Dynamics Reveal How to Empty Bottles Faster

sarah JonasResearch Results

Researchers from the Indian Institute of Technology Roorkee have discovered how to make bottles empty faster, which has wide-ranging implications for many areas beyond the beverage industry. In this week’s Physics of Fluids, they explore this bottle-emptying phenomenon from the perspective of bubble dynamics on a commercial bottle by using high-speed photography. Image analysis allowed them to conceptualize various parameters, such as liquid film thickness, bubble aspect ratio, rise velocity and bottle emptying modes.

Simulations Show Effects of Buoyancy on Drift in Florida Current

sarah JonasResearch Results

Acquiring a better understanding for how objects drift in the ocean has importance for many uses, but most models lack a systematic approach. One new effort looks to provide a clearer alternative. Researchers have released the results from an experiment aimed at tracking different objects as they drift in the Florida Current. Using satellite data, the group developed a new model for how objects drift. They discuss their work in this week’s Physics of Fluids.

Following the lizard lung labyrinth

sarah JonasResearch Results

Mammals inhale oxygen-rich air and they exhale depleted air, exhibiting a so-called tidal flow pattern. In contrast, bird breath travels through part of the respiratory system, but in a one-way loop throughout most of the lung. Biologists have discovered that Savannah monitor lizards have lung structures that are hybrid system of bird and mammal lungs.

Insects’ Drag-Based Flight Mechanism Could Improve Tiny Flying Robots

sarah JonasResearch Results

Thrips don’t rely on lift in order to fly. Instead, the tiny insects rely on a drag-based flight mechanism, keeping themselves afloat in airflow velocities with a large ratio of force to wing size. In a study published in this week’s Journal of Applied Physics, researchers performed the first test of the drag force on a thrip’s wing under constant airflow in a bench-top wind tunnel. Drawing from experience in microfabrication and nanomechanics, they created an experiment in which a thrip’s wing was glued to a self-sensing microcantilever.

Gallery of Fluid Motion: Capturing Liquids and Gases in Action

sarah JonasResearch Results

Tears stream down your face. A beer flows down the side of a pint glass. Fluid mechanics is central to understanding the world around us. The beauty of fluid motion was on display last week in Seattle, where more than 3,000 scientists gathered for the 72nd Annual Meeting of the American Physical Society’s Division of Fluid Dynamics. Created in 1987, the Gallery of Fluid Motion (GFM) is the premier visual record of contemporary fluid mechanics.

Schedule for the APS DFD Press Conferences with Live Webcasts from Seattle

sarah JonasAnnouncement

Press conferences for the 72nd Annual Meeting of the American Physical Society Division of Fluid Dynamics in Seattle will be held Monday, Nov. 25, at the Washington State Convention Center. The conferences, which will be webcast, will focus on research into how flow control is making some MLB pitchers nearly unhittable, predicting tornado formation from the sounds that storms make and teaching fluid mechanics through dance, as well as other discoveries in fluid dynamics.

Fluid Dynamics Provides Insight into Wildfire Behavior

sarah JonasResearch Results

The Kincade Fire has been burning through Sonoma County, displacing people from their homes and leaving destruction in its wake. It is a stark reminder of the increasingly pressing need for a better understanding of how fires begin and spread. This is where Rodman Linn and his research come in. He develops and uses computational models of the coupled interaction between the wildfires and surrounding atmosphere at Los Alamos National Laboratory. In the November 2019 issue of Physics Today, Linn describes a few of the many ways that fluid dynamics controls the behavior of fires.

Analysis of Galileo’s Jupiter Entry Probe Reveals Gaps in Heat Shield Modeling

sarah JonasResearch Results

The entry probe of the Galileo mission to Jupiter entered the planet’s atmosphere in 1995 in fiery fashion, generating enough heat to cause plasma reactions on its surface. The data relayed about the burning of its heat shield differed from the effects predicted in fluid dynamics models, and new work examines what might have caused such a discrepancy.

Stabilizing Multilayer Flows May Improve Transportation of Heavy Oils

sarah JonasResearch Results

During the past 20 years, the oil industry has begun to transition away from light oils toward heavier oils. But transporting heavy oils cost-effectively is a challenge because heavy oils are viscous — essentially a thick, sticky and semifluid mess. One way to outmaneuver this problem, reported in Physics of Fluids, is a viscoplastic lubrication technique.