AFT Blog

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.

In AFT Fathom and AFT Impulse, it is possible to model a submerged pump where a short and possibly frictionless suction pipe for the pump’s inlet does not need to be modeled.  When modeling a submerged pump, there are two options available for specifying the system inlet boundary condition at the pump suction.  As shown in Figure 1 below, the Submerged Pump’s Suction Pressure can either be specified as “Head (HGL)” or “Pressure”.   Modeling a submerged pump is not the only time where the “Head (HGL)” or “Pressure” choices will arise.  If an Exit Valve (i.e., a valve that discharges...

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.

AFT Fathom can easily generate a pump and system curve for your piping system.  Creating a pump and system curve for a simple system with a single flow path and no control features is an easy and typically well-understood process.  However, as piping systems are quite complicated with lots of branch points, control features, and dynamic interactions, creating a useful system curve can quickly become a common source of confusion.  This three-part blog series is going to help clarify concepts regarding pump and system curves to better understand them.   This Part 1 blog will discuss the basics of what pump...

Have you ever finished running an AFT Impulse model and then received the following Warning message shown in Figure 1 and then wondered what it means? During a waterhammer analysis, the flowrates are constantly changing all throughout the system, therefore, the velocities and Reynold's numbers are also constantly changing.  The friction factors will also be constantly changing during the transient.  By default, AFT Impulse will use the friction factors that are obtained during the steady-state analysis and then use the same friction factors during the transient and they will be assumed to remain constant. Since it is possible for the flowrates...

Twenty years ago today I was working desperately on putting the finishing touches on AFT Impulse 1.0. At the time, AFT was a pioneer in every sense of the word. AFT was the first and only company developing visual, drag-and-drop pipe flow modeling software for Microsoft Windows. And AFT Impulse was set to become the world's first visual waterhammer software for Windows. We already had orders for AFT Impulse before it was complete, such was the demand!

Previously, we talked about the Graph Guide, creating Stacked graphs and Dual-Y graphs, and visualizing the results using Animated graphs. This final installment will focus on the various ways to format graphs so they are exactly how you want them to look. In general, there are several ways to set the formatting for the various parts and regions of a graph. I will start with the model we made in the previous blog – the AFT Impulse model, ‘Pump Startup With Event Transient.imp’, which is installed in the Examples folder. Many of the formatting options are gathered together on the Formatting...