AFT Blog
A few weeks ago, a major milestone was passed when AFT Impulse experienced it's Silver Jubilee - which is another word for 25th Anniversary. On November 21, 1996, AFT released the world's first visual waterhammer modeling software for Windows. This is significant for a few reasons including a reminder to me that I am getting really old! At the mome...
Flow going backwards through a pump? Then the pump starts rotating in reverse? Where the heck is the check valve to stop the flow? These are all great questions (which I will answer later in this article). Theodore von Kármán and Robert Knapp were working on these questions in the early 1930's. Most engineering students encounter von Kármán in thei...
When I wrote AFT Impulse 1 back in 1996, I slipped in an undocumented feature to make it capable of modeling the first waterhammer project I did in industry. Since then, this feature had a secret (i.e., undocumented) way of being enabled. AFT Impulse 8 will be released any day, and we have finally made this feature accessible to all. In the User Op...
In June 2020, AFT's Reinaldo Pinto presented the webinar Calculating Transient Forces for Pipe Stress Analysis. The webinar focused on generating unbalanced forces due to surge in AFT Impulse and exporting them to CAESAR-II. During the webinar, 28 questions were asked. Below are the responses. Download the presentation: www.aft.com/...
Really? Another blog about features in AFT software? Yes, really. And there is a good reason for it. Because this new feature in AFT Impulse 8 will change your life. Well, it may not change your life, but it will forever change how you do your waterhammer analysis. I am talking about the new multi-scenario graphing and animation feature. This brand...
I have received questions from clients using AFT Impulse where they ask something like "I closed this valve. Why is the maximum pressure spike way over there and not at the valve?" This comes from years of developing a "common sense" adapted to steady-state flow. With steady flow, a change between states of equilibrium has a local effect that...
AFT Fathom XTS and AFT Impulse have long been able to start events like pump trips or valve closures when a certain condition is met in the system. For example, a valve can close when a tank is full, or a pump can trip when the flow is too low. However, complex systems often have multiple conditions that can cause an event. The pump may trip when the flow is too low OR the suction pressure is too low. The valve may only close when two tanks are full. AFT Fathom version 10 and AFT Impulse version 7 enhance the transient capabilities to allow the definition of these complex Multi-Condition Events.