Available online at www.CivileJournal.org Civil Engineering Journal (E-ISSN: 2476-3055; ISSN: 2676-6957) Vol. 7, No. 10, October, 2021 1787 Study of Pressure Distribution on an Irregular Octagonal Plan Oval-Shape Building Using CFD Arun Kumar 1 , Ritu Raj 1* 1 Research Scholar, Department of Civil Engineering, Delhi Technological University, Delhi, India. 2 Assistant Professor, Department of Civil Engineering, Delhi Technological University, Delhi, India. Received 03 August 2021; Revised 16 September 2021; Accepted 23 September 2021; Published 01 October 2021 Abstract This paper aims to study the wind flow characteristics and to analyze the wind pressure distribution on the surfaces around an irregular octagonal plan shape building model. There is a central open space in plan to provide more surface area around the building for natural ventilation. Plan area of the building is 300 m 2 (excluding the open space) and height is 50 m. Steady state flow of wind with 5% turbulence (moderate turbulence) under atmospheric boundary layer has been taken in the study. Numerical simulation with standard k- model using ANSYS (CFX) software has been used for the purpose. Flow characteristics has been studied in terms of flow separation, reattachment of flow, creation of wakes and vortices. The surface pressure generated around the model has been studied in terms of coefficient of pressure. The model is symmetrical about both the axes in plan. Hence, study for different wind angle of attacks from 0° to 90° @ 30° interval has been conducted. The flow characteristics and unusual or critical coefficient of pressure on surfaces of the model observed have been discussed. Keywords: Oval plan-Shape Building; ANSYS (CFX); Wind Pressure Coefficient; k- model. 1. Introduction Wind pressure is an important factor governing the natural ventilation, pedestrian comfort and design of tall buildings. Computational Fluid Dynamics (CFD) modelling is a convenient, economic and faster solution to access the wind pressure in tall buildings of various architectural shapes specially during the preliminary stage of finalization of any project. Through numerical simulation, wind response on tall buildings for structural variables like moments, loads, pressure etc. can be calculated up to a level of acceptable accuracy. For understanding the natural ventilation in buildings wind pressure is the primary characteristic whereas the force and moment it exerts on structure may be utilized for structural resistance and stability. ANSYS (CFX) is one of the numerical simulation tools that is used for analysing the wind pressure on tall buildings. In ANSYS (CFX) complex geometry of buildings can be easily modelled and discretization of geometry into smaller elements for numerical analysis with good quality meshing can be achieved with full control. Changes in the geometry and meshing can also be easily done for parametric studies. Wind flow is a complex phenomenon and it has a typical behavior to exert differential velocity and pressure around any bluff body coming in its way of flow direction. Though, for ease in analysis a time averaged steady state of uniform flow condition is taken, wind does not flow with a uniform speed and in a constant direction. Wind speed * Corresponding author: rituraj@dtu.ac.in http://dx.doi.org/10.28991/cej-2021-03091760 © 2021 by the authors. Licensee C.E.J, Tehran, Iran. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC-BY) license (http://creativecommons.org/licenses/by/4.0/).