Nozzle-to-ground distance effect on nondominated solutions of multiobjective aeroacoustic flame deflector design problem

Tomoaki Tatsukawa, Taku Nonomura, Akira Oyama, Kozo Fujii

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


This study explores multiobjective aeroacoustic designs for flame deflector of a launch pad. The acoustic characteristics associated with deflector shapes are identified by multi- objective evolutionary computation with large eddy simulations. The objective functions in the multiobjective aeroacoustic design are designed to minimize (1) the spatial-averaged sound pressure level near the payload fairing, (2) the time-averaged maximum pressure on the curved surface of the frame deflector, and (3) the deviation of the curved surface from the at plate inclined at 45° The multiobjective evolutionary computation requires 2500 large eddy simulations. Evaluation of each single configuration required 130 nodes (1040 total cores) of a “K” supercomputer and 6 hour calculation. As the result of optimization, 146 nondominated solutions are obtained. The analysis of nondominated solutions clearly reveals various trade-off relations and correlations among the objective functions. The flow field analysis shows that as the curved surface around the impingement region becomes steeper, weaker acoustic waves are generated in the impingement region. This trend is related to the size of the separation bubble near the impingement region; as the surface steepens, the bubble shrinks. Furthermore, analysis of the effect of nozzle-to-launchpad distance on nondominated solutions are conducted to extract more useful knowledge for rocket launch site design.

Original languageEnglish
Title of host publication21st AIAA/CEAS Aeroacoustics Conference
PublisherAmerican Institute of Aeronautics and Astronautics Inc, AIAA
ISBN (Print)9781624103674
Publication statusPublished - 2016
Event21st AIAA/CEAS Aeroacoustics Conference, 2015 - Dallas, United States
Duration: 2015 Jun 222015 Jun 26

Publication series

Name21st AIAA/CEAS Aeroacoustics Conference


Conference21st AIAA/CEAS Aeroacoustics Conference, 2015
Country/TerritoryUnited States


Dive into the research topics of 'Nozzle-to-ground distance effect on nondominated solutions of multiobjective aeroacoustic flame deflector design problem'. Together they form a unique fingerprint.

Cite this