Vibration and Resonance Issues in Turbomachines

by Arsalan Adil on Nov 29, 2017 3:09:18 PM

Structural vibration is a natural phenomenon exhibited by all structures, by virtue of simply possessing mass and having an associated structural stiffness. Thus, any structure or assembly of structures, with a mass attribution, will possess some structural stiffness. This stiffness will characterize the vibrational response of the structure, depending on the type of boundary conditions constraining the structure. For complex structural configurations, this vibrational response can be determined by numerical techniques, such as the finite element method, which allows calculation of the natural frequencies of vibration of the structure and the respective mode shapes of vibration associated with each of these natural frequencies.


How did I get from not knowing (or caring) anything about home-built aircraft to owning a gas turbine powered helicopter? As you might imagine, it’s complicated.

Ground Source Heat Energy Storage for Power Generation

by Francis A. Di Bella, P.E. on Nov 15, 2017 3:28:25 PM

Have you ever been to the beach on a very hot day? Then I am sure you noticed that the sand is very, very hot, uncomfortably so. Congratulations, you have had first-hand experience with ground source energy storage! Now, as you were hopping across the burning sands, seeking out tufts of grass to cool your burning feet, did you ever wonder how to harness the energy stored in the sand? I have, because it’s too hot for me to read on the beach and sand is a great place to draw diagrams and write equations.


The Value of Visualizing Velocity Vectors

by Mark R. Anderson on Nov 9, 2017 11:12:39 AM

Beyond being a fun tongue twister, visualizing the velocity vectors is probably the most useful and intuitive information available in turbomachinery design. Many fundamental parameters can be gleaned directly from these triangles. These include: flow coefficient, work coefficient, stage reaction, de Haller number, diffusion factor, and diffusion ratio, to name just a few. A great many design rules are predicated on these parameters in the initial design process, which is generally geared to target velocities as the starting point, rather than a predetermined geometry.


Who has not dreamed of living on an island? You’re getting away from it all, walking alone along a secluded beach, as the ocean gently laps at shore…ahhhh. Excuse me – I have to go search for vacation packages!


OK, I’m back. Ironically, the very thing that attracts people to islands is the same thing that makes them a nightmare to live on when disasters strike - being “cut off” from the mainland. A recent example is Puerto Rico, where Hurricane Maria roared through with 190 mph winds that completely wiped out the power across the island. Well over a month later, most of the island is still without power and clean drinking water is in short supply. It will take years for the island to recover.


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