Pulsation in fluid systems...Is it steady-state or is it transient? Well, it is both. Kind of. Pulsation causes periodic transients that are regular in nature and thus considered steady-state. It can be called "steady-state pulsation".
The problem is not whether pulsation is steady-state or transient. It is whether the frequencies that are excited by the pulsation are at or near the acoustic resonant frequencies of the fluid system. If so, there can be problems. API 674 defines the allowable pulsation limits for positive displacement pumps.
AFT will soon release the new PFA module for AFT Impulse. PFA stands for Pulsation Frequency Analysis. This new module will help engineers predict, understand and avoid resonant frequencies related to the fluid acoustics. It will also help engineers assess whether their system is in compliance with API 674.
I am not a political commentator. But anyone not living in a cave has to admit that the past year of American politics was just plain wacky. For those of you for whom English is not your first language, "wacky" is a word that basically means (by my personal definition) "strange, highly unusual and a bit crazy". Which also applies to Donald Trump.
Donald Trump was sworn in as the 45th American President two days ago on Friday, January 20th. I spent Friday and the rest of this weekend pondering this and what it might mean for those who work in technology.
What actually happens under President Trump is anyone's guess at this point. Leaving aside (to the political commentators) all of the wacky things President Trump has said, I am going to take some time here to speculate on what it means for technology. I am talking of technology here in a broad sense, and not the ridiculously narrow sense one often sees it portrayed - as if Silicon Valley technology is the only technology which is important.
Yesterday was the 75th anniversary of the Japanese attack on Pearl Harbor which catapulted the United States into World War II. For Americans, there was no way to miss the abundant news coverage and the stories of vets who were there that day and are still alive today to share their experiences. As I read about and watched some of the ceremonies and news it got me thinking about the astounding progress humankind made in the 20th century in the field of aviation.
The Wright brothers made their first successful, sustained flight on December 17, 1903 near Kitty Hawk, North Carolina. That in itself was an astounding accomplishment. Their Wright Flyer aircraft today resides in the Smithsonian National Air and Space Museum in Washington, D.C. (see below a photo I took in 2008). I could spend days at that museum and the extended air and space museum in Virginia, but alas I only have had time to spend one day at the main museum in Washington D.C. and have not had an opportunity to visit the one in Virginia.
A little over 30 years ago I made a mistake. At the time I was a busy undergraduate student in mechanical engineering in California. Some students put together an official weekend trip for ME students to the Hoover Dam that included a special tour of the dam geared towards engineers and engineering students. I remember having tons of homework to do and decided not to go on the weekend trip. That was a mistake and I have regretted it ever since.
One outcome of that mistake is that I have rarely, if ever, missed another chance to go on a technical tour. Another outcome is that I have been trying to fit in a Hoover Dam visit ever since. I have been to or through Las Vegas (about 45 minutes from Hoover Dam) probably 30 times since then. But I could never find that half-day I needed to visit the dam with the other priorities I was trying to balance (usually involving my family that included four children). Until a couple of weeks ago.
Another twist for me involves the professor who taught me Statics (the study of stationary structures like dams). I was incredibly fortunate to take a Statics class when I was 19 years old from Howard Eberhart. He was an outstanding teacher and memorable character. Professor Eberhart towered over most of us students at 6' 4" (1.93 m) in height. I will never forget his steely blue eyes, bald head, and deep, gravelly voice proclaiming (for the hundredth time), "It is all...simple...statics!".