# Richard Smith's blog

## Flying Jellyfish

It seems that a day doesn't go by without the announcement of a new and innovative flying drone. Joining the throng we have researchers from New York University (NYU) who have developed a drone that flies like a jellyfish, but without the sting! Their work was showcased at the 2013 APS Division of Fluid Dynamics Meeting.

Flying Jellyfish-Like Drone

## Airplane + Helicopter + Hovercraft + Airship = ESTOLAS

What do you get if you cross an airplane with a helicopter, with a hovercraft, with an airship? The European Commission's Extremely Short Take Off and Landing on Any Surface (ESTOLAS) project.

ESTOLAS Concept Aircraft

## Inspiration from Spinning Maple Seeds

Looking to nature for inspiration (biomimicry) is nothing new. I've already covered turbine blades inspired by humpback whale fins and drag-reducing textures that mimic shark skin, so next up we have the elegant spinning maple seed.

CFD Simulation of a Spinning Maple SeedLeading edge vortex shown by streamlines

## CFD Study Comparing Racecar Wing Mounts

A growing trend among racecar designers is to use a 'swan neck' wing mount that attaches to the pressure surface of a wing. Historically wing mounts have connected to the suction surface of a wing. What difference does the wing mount strategy make to overall car downforce and drag? Let's investigate using Computational Fluid Dynamics (CFD) on a BMW Z3 - the same model I used in a previous CFD study to show how effective adding a wing is to increase downforce.

CFD Simulation of a Racecar with a 'Swan Neck' Wing MountStream ribbons colored by velocity magnitude

## CFD Study of a Car With and Without a Wing

What difference will adding a rear wing to a car make? You can expect an increase in downforce, equivalent to a reduction in lift, and an increase in drag. To quantify these effects I simulated the aerodynamics of a BMW Z3 using Computational Fluid Dynamics (CFD) without a wing and with a wing.

CFD Simulation of a Car with a Rear WingVelocity contours and streamline arrows

## Failure to Simulate

Given the availability of Computer Aided Engineering (CAE) analysis tools, such as Computational Fluid Dynamics (CFD), it is a surprise that analysis tools are not used more by architects during building concept design, especially relative to the local environment around a building.

CFD Simulation of SkyscrapersAir Velocity Vectors

## Wind Tunnel Reveals Dinosaur's Flight Secrets

Researchers at the University of Southampton have tested a model of a Microraptor (a feathered, four-winged dinosaur) in a wind tunnel and found that it was optimized for slow gliding. Its multiple wings performed the same function as a modern-day, high-lift configuration used on airliners for takeoff and landing.

MicroraptorSketchUp Model

## The Great Sphinx CFD Wind Erosion Study

There are many erosion processes that relate directly to either water or air flow. And if it flows, then Computational Fluid Dynamics (CFD) can help. So it should come as no surprise that CFD was used to better understand and predict the wind erosion on the Great Sphinx in Egypt.

Caedium CFD Simulation Around The Great SphinxRendered in POV-Ray

## Automated CFD Angle of Attack Sweep for an Airliner

Often in a Computational Fluid Dynamics (CFD) study you will find yourself repeating a series of operations that are prime candidates for automation. For instance, performing an angle of attack (alpha) sweep for an airplane configuration is a great example where automation can be a significant time saver as I will demonstrate.

CFD Simulation of an AirlinerAlpha = 6 degrees, velocity contours and arrows

## CFD Simulation of a Pitot Tube and Manometer

Pitot tubes are critical devices used to determine the airspeed of an aircraft. In aerodynamics it is important to know the speed of an aircraft relative to the surrounding air to alert pilots to stall conditions. Pitot tubes are also used in wind tunnels to determine airspeed, sometimes using a manometer to measure the pressure difference between static pressure and total pressure to determine the dynamic pressure. I thought it would be interesting to see if we could simulate a pitot tube connected to a manometer (two-phase flow, air + water) using Computational Fluid Dynamics (CFD) and to share my findings with you.

CFD Simulation of a Pitot Tube and ManometerBlue is water and red is air