Bubbly Curtain/Water Deluge Noise Reduction Investigation with Applications to Supersonic Jet Noise; 24-000007914
Abstract
The purpose of this action is to provide a FY25 CR2 funding increment.--Tactical jet noise reduction remains a challenge for the Navy, particularly in ensuring noise reduction does not result in reduced thrust. Proposed is a three-year collaborative research program between Virginia Tech (VT) and Brigham Young University (BYU) to assess the effectiveness of a bubbly curtain/water deluge system as a noise reduction technology for protecting naval personnel exposed to high levels of noise from supersonic tactical jets. A water curtain located between the jet exhaust and personnel creates a barrier with large impedance mismatch. The bubby curtain concept injects air bubbles into the water barrier and takes advantage of both the mismatch in acoustic impedance and the presence of bubbles in the water, which may add additional reflection, refraction, and resonance-induced absorption of the sound waves. An advantage of the proposed concept is it does not require any engine or aircraft modification, and thus, has no adverse effect on thrust. The proposed research#s primary objective is to develop and deliver a design for a water curtain deluge system for reducing supersonic jet noise from a tactical aircraft at afterburning conditions. To achieve this objective, the following, interrelated steps will be carried out:1.Develop a modular/reconfigurable water deluge system with variable bubble creation2.Perform proof-of-concept baseline noise reduction measurements at relevant conditions using the afterburning supersonic jet noise rig at VT.3.Determine acoustic transmission as a function of water barrier properties and geometric parameters through analytical models and laboratory experiments at BYU4.Using a numerical framework and equivalent source models of laboratory and full-scale afterburning jets, parameterize and optimize a water curtain design for afterburning jets at BYU5.Quantify noise reduction of laboratory-scale afterburner jet noise at VT6.Deliver final design recommendations for a full-scale water barrier deluge system with performance predictions. The study will seek to demonstrate that the theories and methods developed in the analytical, numerical, and laboratory investigations accurately predict reduction of supersonic jet noise at afterburner conditions. Baseline data obtained with and without the water curtain will also aid in validation of other computational models being developed. The proposed effort has high Naval relevance. The ONR Jet Noise Reduction (JNR) program stems from tactical aircraft noise#s health and environmental impacts, which reduce training operations tempo and mission readiness. The proposed JNR effort is more than a proof-of-concept as it will go from initial concept through detailed physical acoustics investigations to demonstrating the system can effectively mitigate supersonic jet noise at relevant conditions. The JNR solution is novel because the system is external to the engine, ensuring no loss in engine performance. Furthermore, the availability of water for generating a bubbly water curtain at sea makes it a relatively low-cost and easy-to-implement solution, with the potential for noise reduction exceeding 10 dB. The proposed effort will result in training of 3 graduate students and at least two undergraduate students in Navy-relevant topics such as physical acoustics, aeroacoustics, noise control methods, combustion, and laboratory practices. APPROVED FOR PUBLIC RELEASE
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 10, 2025
- Source ID
- N000142512184
Entities
People
- Joseph Meadows
Organizations
- Office of Naval Research
- United States Navy
- Virginia Tech