Hello, I am doing a project which includes attempting to map a theoretical pressure distribution across a capillary tube. I am trying to do a finite element analysis using Hagen-Poiseuille's Law to map the theoretical pressure distribution before I move onto using a SolidWorks Flow Simulation. The problem is that, I keep getting values that seem way too high and suggest things that I believe are not possible for the problem (like supersonic flow). A basic physical description of the problem: There is a 5 ft section length of capillary tube, which is held at a constant Pressure of 10 psig across its length. Then at time t = 0 the tube is pierced at one end so that the pressure at that point is atmospheric Pressure. I would like to be able to use Finite Element Analysis utilizing Hagen-Poiseuille's Law to create a pressure distribution across the capillary tube for each time step. Some dimensions about the scenario: CAPILLARY TUBE DIMENSIONS: Length = 1.524 m, Diameter = 0.00635 m. I am wanting to break this up into 5 sections (dx = 0.3048 m) for the finite element analysis. Pressure = 68947.6 Pa (10psig) ***For time = 0, I have assumed that the pressure drop across section 1 is 10 psig, and there is no change in pressure from the subsequent sections, it will be clearer in the image I attach Gas = Air (R_air = 287.06 J/(kg*K)) Time_step = 8.89e-04 s ***I have been assuming this time step based on how long itwould take a pressure wave at the speed of sound to travel one section length (0.3048m) I am going to attach an image below of some of my hand calculations because I think it will illustrate better than I can in my text. I would greatly appreciate any insight!