This paper examines a waterhammer event caused by the partial closing of a valve in a relatively simple system. The hydraulic transient analysis is performed using AFT Impulse, and the mechanical system response is then evaluated using Intergraph’s CAESAR II ® pipe stress analysis software.
Periodically, AFT Arrow users pose the question of what CdA value to use for modeling choked flow through an orifice. This paper reviews the subject to provide guidance in this area. As explained in this paper, there is not one answer— AFT Arrow provides several options in modeling an orifice, perhaps the two most commonly used being the Sharp-Edged and Cd (discharge coefficient) orifice models.