Numerical simulations in obtaining drag reduction for projectile with base bleed

Belaidouni, Habib; Živković, Sanja; Samardžić, Marija

doi:10.5937/str1602036b

Cited by 8 publications

(10 citation statements)

References 6 publications

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“…The LES index quality criteria as proposed by I.B. Celik (17) , has been tested on current domain and was found to be 77%, quite close to the suggested verification index by Celik of 80% or above. CFF used for LES_IQ is as follows:…”

Section: Solution Techniquementioning

confidence: 58%

Unsteady aerodynamics computation and investigation of magnus effect on computed trajectory of spinning projectile from subsonic to supersonic speeds

Chughtai¹,

Masud²,

Akhtar

2019

Aeronaut. j.

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This paper describes the extensive numerical investigation carried out on a 203-mm spin-stabilised projectile to study the effects of Magnus force at high angles of attack on the stability and flight-trajectory parameters, for further validation and incorporation in a 6-DOF trajectory solver for flight-stability analysis. Magnus force typically influences the course of flight by causing the projectile to drift from its intended path in addition to generation of inbuilt dynamic instabilities in pitch and yaw orientation and is a function of AoA and spin rate. This study is a consolidation of the authors’ previous research on the same caliber projectile but with time-accurate analysis. It has been found that typically, the Magnus force and moment calculation requires time-accurate Navier Stokes equations to be solved numerically for accurate prediction(1,2). Hence, to complete the extraction of static and dynamic coefficients derivatives, unstructured time-accurate CFD analysis on multiple configurations, ranging from subsonic to supersonic Mach regimes, has been evaluated using Large Eddy Simulation (LES) and found to be suitable for capturing the desired effects. However, the LES simulation requires non-dimensional wall distance (y+) of the order of 0.5 – 1, with LES_IQ > 75% thus, is computationally-intensive. In addition, to cover the entire flight envelope from Charge 1 (249 m/s) to Charge 7 (595 m/s), at spin rate from 500 rad/s to 750 rad/s, 30 cases have been evaluated to generate the time-accurate coefficient library for integration with 6-DOF solver analysis. The results obtained have been compared with the available experimental data and found to be in reasonable agreement. The results of 6-DOF solver, incorporating the extracted coefficients, were compared with firing-table results, which further validated the computational methodology. This study provides an insight on how opposite flow interacts with the attached boundary layer due to spin rate and generates a turbulent interacting flow with variation in vortical structures for Q-Criterion vortex-flow visualization.

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Section: Solution Techniquementioning

confidence: 58%

Unsteady aerodynamics computation and investigation of magnus effect on computed trajectory of spinning projectile from subsonic to supersonic speeds

Chughtai¹,

Masud²,

Akhtar

2019

Aeronaut. j.

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“…The wind tunnel tests were performed by varying the pressures from high-pressure air supply so the different mass flow rates were achieved. Numerically obtained base-bleed parameters, given by the designer of the projectile [13], were the only input in the experimental setup design. The wind tunnel tests of the projectile were performed in the Mach number range from 1.5 to 2.…”

Section: Resultsmentioning

confidence: 99%

“…Drag force coefficients were numerically predicted for the Mach number from 0.99 to 2.1 at different flight regimes, [13]. Numerical steady state simulations of the base-bleed effects on aerodynamic characteristics of the projectile with two turbulences model were done for each Mach number.…”

Section: Numerical Simulationsmentioning

confidence: 99%

Wind tunnel verification of base-bleed effects on aerodynamic characteristics of an axi-symmetric projectile

Damljanović¹,

Ocokoljić²,

Lisov³

et al. 2021

Sci Tech Rev

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Experimental verification of base-bleed effects on aerodynamic characteristics for the supersonic flight stages was requested during the development of an axi-symmetric projectile. The experimental setup for testing base-bleed configurations of the projectile was designed, built and tested in the T-38 trisonic blowdown wind tunnel of the Military Technical Institute (VTI), Belgrade. Gas-generator was formed from a simple chamber with a single manifold pneumatically connected to a high-pressure air supply. Wind tunnel tests comprised measurement of aerodynamic forces and moments of the projectile with active base-bleed. Flow visualization was performed using the Schlieren method. It was of interest to verify the base drag reduction in the wind tunnel tests and to compare it with numerical predictions. In addition, the experience gained during these tests has been found to be helpful in the design of the future similar wind tunnel setups

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“…The Computational approach was carried out using CFD software. The governing equations are based on Reynolds Averaged Navier Stokes equations (RANS), given by equations for the conservation of mass (continuity), momentum and energy, presented below (Dali et al 2019;Nicolás-Pérez et al 2017;Belaidouni et al .2016). To achieve closure of the governance equations, the k ε − realizable model was chosen in view of its wide use in similar studies (Chang et al 2023;Aziz et al 2020;Torangatti et al 2014;Belaidouni et al 2016), default constant values were employed for this model.…”

Section: Computational Approachmentioning

confidence: 99%

Prediction of Drag Aerodynamic Coefficient of the 155mm Projectile Under Axisymmetric Flow Using Different Approaches

Ferfouri,

Allouche,

D. Jerković

et al. 2023

JSSCM

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The determination of the total aerodynamic load which negatively influences the movement of artillery projectiles is inevitable and indispensable in order to be able to increase or control their ranges. The main part of this aerodynamic load that has the most influence on projectile movement is the drag force, which acts in the opposite direction to the velocity vector and therefore opposes its movement. From this, in this present work, the total drag coefficient of the 155mm M107 axisymmetric projectile under axisymmetric flow, at zero yaw, was predicted by semi-empirical and computational fluid dynamics (CFD) approaches in the three flow regimes, also the influence of its components on the total drag was analysed. The average deviation of the total drag coefficient in the three flow regimes, compared to the reference experimental results, is 5.7% for the semi-empirical results and 1.7% for the computational results. Analysis of the influence of the total drag components, such as pressure drag, friction drag and base drag, permitted to calculate their influence rates on the total drag as a function of Mach number and flow regime.

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Numerical simulations in obtaining drag reduction for projectile with base bleed

Cited by 8 publications

References 6 publications

Unsteady aerodynamics computation and investigation of magnus effect on computed trajectory of spinning projectile from subsonic to supersonic speeds

Unsteady aerodynamics computation and investigation of magnus effect on computed trajectory of spinning projectile from subsonic to supersonic speeds

Wind tunnel verification of base-bleed effects on aerodynamic characteristics of an axi-symmetric projectile

Prediction of Drag Aerodynamic Coefficient of the 155mm Projectile Under Axisymmetric Flow Using Different Approaches

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