Experimental Investigation of Single Expansion Ramp Nozzle (SERN) Flows with 20° Ramp Angle and 1h Cowl

¹ Assistant Professor, Department of Aerospace Engineering, Agni College of Technology, Chennai, India – 600 130
² Assistant Professor, Department of Mechanical Engineering, Agni College of Technology, Chennai, India – 600 130

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Published online: 3 March 2026

Abstract

This experimental study investigates the velocity decay characteristics and mixing performance of a Single Expansion Ramp Nozzle (SERN) operating at low supersonic speeds. A SERN model with a 20° ramp angle and a one-hour cowl was created and tested over a range of low Nozzle Pressure Ratios (NPRs) of 3 to 6. The primary goal was to map the entire pressure field and measure the rapid loss of kinetic energy (velocity decay) downstream from the nozzle exit. A Pitot tube with a three-dimensional traverse mechanism was utilized to collect total pressure data along mutually perpendicular transverse axes at various axial locations (X/h and z/h). To ensure accuracy, a high-precision pressure scanner and indicator were utilized. Important data for assessing the SERN's performance at improving jet-ambient fluid mixing. The findings provide knowledge needed to adjust SERN geometry for increased propulsion efficiency.