CFD Letters 16, Issue 4 (2024) 120-133 120 CFD Letters Journal homepage: https://semarakilmu.com.my/journals/index.php/CFD_Letters/index ISSN: 2180-1363 Effect of Roll Angle Configurations of a Reverse Delta Type Add-on Device on Wing Tip Vortex Alleviation Afaq Altaf 1 , Mohammed Abdulmalek Aldheeb, 2,* , Ashraf Ali Omar 3 , Waqar Asrar 2 1 42 Abu Dhabi, Abu Dhabi, UAE 2 Department of Mechanical and Aerospace Engineering, International Islamic University Malaysia (IIUM), Kuala Lumpur, Malaysia 3 School of Aerospace and Automotive Engineering, International University of Rabat, Recade Rabat-sale, Sala El Jedida, Morocco ARTICLE INFO ABSTRACT Article history: Received 24 September 2023 Received in revised form 21 October 2023 Accepted 18 November 2023 Available online 1 January 2024 An add-on device in the shape of a reverse delta has shown the ability to alleviate wake vortices. The present work studies the interaction of the wing tip vortex and the reverse delta type add-on device vortices. This paper looks at the vortex interactions generated downstream of the wing tip in planes perpendicular to the free stream direction and their dependence on roll angles φ at a mean chord-based Reynolds number of Rec=2.75×10 5 . The study reveals that the add-on device causes a reduction in the tangential velocity V  and vorticity of the resultant vortex by up to 44.1% and 59.4%, respectively. Also, it is found that the resultant vortex core radius increased by 305%. The results indicate that the reverse delta type add-on device implants countersign vorticity into the wing tip vortex and modifies its roll-up process. Keywords: Add-on device; Vortex; PIV; Wing tip 1. Introduction Continuous air traffic growth demands novel ideas to be explored in the aviation industry so as to overcome the problem of hazardous wake vortex encounters. The objective of these novel ideas is to decrease the aircraft spacing during the take-off and landing phases of flight while upholding the same level of safety. Present separation rules are not adequate to deal with the air traffic demands of the future as additional spacing between aircrafts is allowed than is actually required to avoid air traffic accidents as mentioned by Babie [1]. Adding more runways to airports is not a practical solution as most large airports are close to major metropolitan areas where expansion would be difficult and expensive. Fatal aircraft accidents have occurred at low altitudes during landing approaches due to wake turbulence because of inadequate time and altitude for pilots to recover full control of the low altitude aircraft when they fly into strong trailing vortices of an earlier large aircraft according to Veillette [2]. Since it is impossible to avert aircraft wake vortices, ways of diminishing their strength have to be considered. * Corresponding author. E-mail address: aldheeb@iium.edu.my (Mohammed Abdulmalek Aldheeb) https://doi.org/10.37934/cfdl.16.4.120133