Computational fluid dynamics (CFD) is a tool with amazing flexibility, accuracy and breadth of application. But the tools need to be properly applied in order to deliver insight and value. Nobody starts out as an expert in CFD software. Instead, we all progress from beginners to experts over time.
For example, when I first became interested in cycling, I went shopping for a new bike. I needed something better than the old junker I was riding at the time but was a bit intimidated by cycling technology. Those small, hard saddles looked plain uncomfortable! Skinny tires! And clipless pedals were a mystery. So I ended up with a “cross” bike. Continue reading
I don’t know about you but I want the best I can get — whether I’m doing CFD prep and meshing or just living my life. It had better be good and speedy and easy — I want it all! Unfortunately, life doesn’t work always that way.
For example, I have a beautiful wrought iron fence in front of my house. The problem is that the fence is made of steel and as we all know, steel has the unfortunate property of rusting as the paint ages and loses integrity. So, this summer I have a big project to scrape, brush and repaint the metal. I’m not looking forward to the many hours of hands on time that will take! Continue reading
There’s an old project management adage that goes “Good. Fast. Cheap. Pick any two.” There are tons of websites and blogs about it. I’m particularly fond of this one about the designer’s holy triangle. Unfortunately, this holds true in the engineering simulation world. With “good” meaning “accurate,” you’re stuck with suboptimal choices: Good + fast = expensive; good + cheap = slow; fast + cheap = inferior. Product designers are stuck with good results that take too long or “directional” results fast. Good and fast just was not on the table. Continue reading
As I am sure you know, ANSYS general-purpose CFD codes are applied across such diverse industries as off-road (construction) vehicles, alternative energy, and oil and gas. This requires us to develop software that meets the modeling needs of the world’s largest user-base of engineering simulation. Which means our code can’t be everything to everyone. That is why we provide users with the ability to incorporate their own industry-specific capabilities. This level of openness that creates the opportunity for our users to implement their own cutting edge physics. This post will talk about how general-purpose CFD tools can be customized to model blood damage in medical devices. Continue reading
Turbomachinery can be the most rewarding of CFD simulations. At the same time, it can be the most challenging.
Turbomachinery covers a broad range of products including compressors, turbines (gas, hydraulic, steam, wind), turbochargers, pumps, fans and more. And turbomachinery users demand ongoing improvements, such as increased efficiency, reliability and durability while reducing emissions (for those involving combustion) and noise. Continue reading
Fidelity and accuracy is critical in CFD simulation. After all, physical prototyping and testing can only be reduced and even replaced by CFD if one can expect accurate results. Up to now, high fidelity, high accuracy results came with a price. Complex geometries — the realistic, no holds barred type — required hours of manual effort to clean up the model and then prepare the mesh. Users were tempted to cut corners and take short cuts that sped up prep but took a toll on accuracy and fidelity. Unfortunately, there is no way of knowing just how those inaccuracies skewed the results, putting any recommendations in doubt. For example, if you don’t resolve a boundary layer correctly then any aerodynamic drag figures could be highly inaccurate. Continue reading
Clean water is one of the most basic necessities of our lives. Our health depends on it. What transpired in the Flint water crisis in Michigan recently has shocked the nation. President Obama declared a state of emergency and there are demands that the Governor of Michigan steps down. It all started when, in order to reduce cost, the City of Flint officials decided to use Flint River water for residential consumption without adding orthophosphate, a chemical that coats the pipe interior thereby inhibiting any leaching of lead. Continue reading
Winter has arrived in the northern hemisphere and with it comes snow. Snow complicates our lives — roads become slick with ice and drifts can block our way. When it piles up high on mountains, avalanches can wreak havoc.
Simulating pumps is hard!
Pumps, by their very nature, include moving and rotating parts so it is essential to allow this motion during the simulation. Positive displacement pumps move the fluids by mechanical action so, the need to accurately model the motion of the components increases even more. To add to that, every detail counts. Capturing tiny details such as leakages of just a few microns along with motion of the rotor makes the problem even more challenging. Continue reading
Extrusion is a high-volume manufacturing process in which any of a multitude of polymers are melted, formed into a continuous profile and then cut to length. The process results in a wide variety of low cost, high volume products that show up in every aspect of our lives from drinking straws, medical tubing and piping to weather stripping, deck railings and window frames. But because they are so common, profit margins can be slim and manufacturers are looking at every angle to find ways to lower costs and increase their margins. Continue reading