Submitted by symscape on September 4, 2013 - 08:32
The ease of Cartesian or wrapper-based meshing for Computational Fluid Dynamics (CFD), including immersed boundary methods, is predicated on having a suitable surface mesh (e.g., STL) as an input. That surface mesh has certain constraints that, if not satisfied, will either cause a poor final mesh or can cause the Cartesian meshing process to fail.
CFD Cartesian MeshSource: Richard Smith EngD Thesis 1996
Submitted by Richard Smith on August 27, 2013 - 12:26
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
Submitted by Richard Smith on August 15, 2013 - 12:35
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
Submitted by Richard Smith on July 22, 2013 - 07:44
Welcome to the concluding episode of my two-part project to compare results between the virtual wind tunnel and free air using a series of Computational Fluid Dynamics (CFD) simulations. Recall that the previous post outlined the free air tests and expectations for the comparison. Here I present the results and conclusions.
CFD Simulation of a Racecar in a Wind TunnelPressure contours on the racecar
Submitted by Richard Smith on July 16, 2013 - 08:22
Often the ultimate aim of performing a wind tunnel test on a scale model is to provide data on how the full size equivalent will behave in free air. This is especially true in motor racing (e.g., Formula 1) where teams use a combination of wind tunnels and Computational Fluid Dynamics (CFD) to guide what they hope is a winning racecar design. As a follow on to my project to build a virtual wind tunnel to test an open wheel racecar, here I start a two-part project to compare results between the virtual wind tunnel and free air using a series of CFD simulations.
Submitted by Richard Smith on June 24, 2013 - 08:23
A Moving Reference Frame (MRF) is a relatively simple, robust, and efficient steady-state, Computational Fluid Dynamics (CFD) modeling technique to simulate rotating machinery. For example, the rotors on a quadcopter can be modeled with MRFs.
MRF CFD Simulation of a Quadcopter in FlightShows streamlines colored by velocity magnitude
Whether 3D printing can live up to the hype remains to be seen. However, making things has been around since time eternal. The fact that 3D printers have reached a price point allowing small businesses and hobbyists, collectively referred to as Makers, to leap on board is definitely exciting. However, what hasn't changed is that building a physical thing still costs time and money. What can we learn from the millennia of building things prior to the availability of 3D printers?
Submitted by Richard Smith on June 11, 2013 - 10:25
Helical strakes are often used on chimneys to reduce vortex induced vibration (VIV). However, these strakes also have a significant drawback - they induce massive increases in drag and side forces that have significant structural implications for the chimney. Read on for a Computational Fluid Dynamics (CFD) study that compares a smooth cylindrical chimney to the same chimney with helical strakes.
CFD Simulation of a Helical Strakes ChimneyVelocity magnitude contours