Development of nonstationary side forces along a slender body of revolution at incidence

Degani, David

doi:10.1103/physrevfluids.7.124101

Cited by 4 publications

(4 citation statements)

References 39 publications

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“…is zero for the short configuration while approaching 0.175 for the long configuration [20]. The fineness ratio has a predominant effect on the unsteadiness of the flow.…”

Section: Effect Of the Fineness Ratio On The Overall Forcesmentioning

confidence: 91%

“…There is a study of a similar configuration at low subsonic flow and low Reynolds number with fineness ratios 10, 15 and 20, which support this idea of increasing instability and unsteadiness with the fineness ratio. At the same angle of attack, the Strouhal number St = f ×D u ∞ is zero for the short configuration while approaching 0.175 for the long configuration [20].…”

Section: Effect Of the Fineness Ratio On The Overall Forcesmentioning

confidence: 94%

“…Then, the oscillations occur at this part, although the different body parts have not been analyzed separately. In the very good detailed work shown in reference [20] it is shown the time histories for the side force coefficients of the ogive and cylinder of a body of fineness ratio of L/D = 20. It is clear that the flow is steady in the nose region, while there is a fluctuating flow with a Strouhal number of St = 0.15 approximately.…”

Section: B Configuration With Fineness Ratio L/d = 15mentioning

confidence: 99%

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Fineness Ratio Effects on the Flow Past an Axisymmetric Body at High Incidence

Jiménez‐Varona

Liaño

2023

Aerospace

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The flow past an axisymmetric body at a sufficiently high angle of attack becomes asymmetric and unsteady. Several authors identified three different flow regions for bodies of large fineness ratio at low subsonic flow and high incidence: a steady region in the forebody and two unsteady regions in the rear body. Unsteady Reynolds Averaged Navier–Stokes (URANS) codes with eddy viscosity turbulence models or Reynolds stress turbulence models fail to capture the unsteady flow region. These methods are overly dissipative and resolve only frequencies far lower than turbulent fluctuations. Scale-Adaptive-Simulation (SAS) provides an alternative method to afford the problem of these massively separated flows at high Reynolds numbers without addressing the problem to Large Eddy Simulation (LES). This paper applies SAS to study the effect of slenderness on the flow. The numerical solutions show that the flow becomes more unstable as the fineness ratio increases, and the three flow regions are clearly recognizable. For low fineness ratios, only one of the two unsteady regions is visible. The good agreement between the sectional forces and pressure coefficients with their corresponding experimental data for an ogive-cylinder configuration allows an analysis of the flow structure with a fair degree of confidence.

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“…is zero for the short configuration while approaching 0.175 for the long configuration [20]. The fineness ratio has a predominant effect on the unsteadiness of the flow.…”

Section: Effect Of the Fineness Ratio On The Overall Forcesmentioning

confidence: 91%

Section: Effect Of the Fineness Ratio On The Overall Forcesmentioning

confidence: 94%

Section: B Configuration With Fineness Ratio L/d = 15mentioning

confidence: 99%

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Fineness Ratio Effects on the Flow Past an Axisymmetric Body at High Incidence

Jiménez‐Varona

Liaño

2023

Aerospace

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“…10 With increasing α, the Kármán-like vortex region expands forward, compressing the steady regions, and leading to a near-zero time-averaged lateral force. Degani 11 used numerical simulations to analyze the development of the Kármán-like vortex region and the unsteady characteristics of lateral forces. The research identified stable components caused by tip vortices and absolutely unstable components caused by nonstationary vortices in the rear body.…”

Section: Introductionmentioning

confidence: 99%

The influence of roll angles on unsteady aerodynamics in a canard‐configured missile

Wei,

Chen,

Tang

et al. 2024

Int Journal of Mech Sys Dyn

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During the initial stage of vertical launch, a missile may exhibit an uncertain roll angle (φ) and a high angle of attack (α). This study focuses on examining the impact of roll angle variations on the flow field and the unsteady aerodynamics of a canard‐configured missile at α = 75°. Simulations were performed using the validated k‐ω SST turbulence model. The analysis encompasses the temporal development of vortices, the oscillatory characteristics of the lateral force, and the fluctuation of kinetic energy distribution within the framework of proper orthogonal decomposition (POD). The results indicate that the flow field surrounding the canard‐configured missile is characterized by inconsistent shedding cycles of Kármán‐like and canard‐separated vortices. A distinct transition zone is identified between these vortices, where vortex tearing and reconnection phenomena occur. With increasing roll angles from 0° to 45°, there is an observed shift in the dominant frequency of the lateral force from the higher frequency associated with Kármán‐like vortex shedding to the lower frequency of canard vortex shedding. The shedding frequency of Kármán‐like vortices corresponds to the harmonics of the canard vortex shedding frequency, indicative of a higher‐order harmonic resonance. The frequency of the lateral force is observed to decrease with an increase in roll angle, except in configurations lacking distinct canard‐separated vortices, which are characterized by a “+” shape. The POD analysis reveals that the majority of the fluctuation energy is concentrated in the oscillations and shedding of the canard‐separated vortices, leading to pressure fluctuations that are primarily observed on the canard and the downstream region of the canard.

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