Statistical properties of spherical shock waves propagating through grid turbulence, turbulent cylinder wake, and laminar flow

Inokuma, Kento; Watanabe, Tomoaki; Nagata, Koji; Sakai, Yasuhiko

doi:10.1088/1402-4896/aafde2

Cited by 5 publications

(1 citation statement)

References 25 publications

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“…Wind tunnels have been used extensively in many studies [1]- [3] commonly including experimental measurements [4]- [13], numerical simulations [14]- [17], and in various flow situations e.g. subsonic, hypersonic [18], [19], transonic [20], [21], laminar, turbulent [22]- [24], etc. In engineering, wind tunnels are used to test the flow around aircrafts, the performance of rotors and turbines [25]- [27], and even studies on the flight of birds [28] and the effects of wind on the shape and growth of plants [29].…”

Section: Introductionmentioning

confidence: 99%

Characterization, Design Testing and Numerical Modeling of a Subsonic-Low Speed Wind Tunnel

Lara

Salazar

2022

Ing.

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Context: Wind tunnels are essential devices in the study of flow properties through objects and scaled prototypes. This work presents a numerical study to characterize an existing wind tunnel, proposing modifications with the aim to improve the quality of the flow in the test chamber. Method: Experimental measurements of the inlet velocity and pressure distribution of a wind tunnel are nperformed. These empirical values are used as parameters to define boundary conditions in simulations. The Finite Element Method (FEM) at low speeds is implemented to determine the stream function by using a standard Galerkin method. Polynomial interpolations are employed to modify the contraction section design, and numerical simulations are performed in order to compare the numerical results of the flow for the existing and the modified wind tunnels. Results: Experimental measurements of the flow at the wind tunnel entrance are presented. The velocity field and distribution of thermodynamic variables inside the tunnel are numerically determined. This computations are useful since it is experimentally difficult to make measurements inside the channel. Additionally, numerical calculations of these variables are presented under modifications in the tunnel geometry. Conclusions: A comparison between these simulations show that laminar flow at low velocities can be modeled as incompressible and irrotational fluid under a bidimensional approximation along its longitudinal section. It is observed that modifications in the geometry of the tunnel can improve the flow in the test section of the wind tunnel in the laminar regime.

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Section: Introductionmentioning

confidence: 99%

Characterization, Design Testing and Numerical Modeling of a Subsonic-Low Speed Wind Tunnel

Lara

Salazar

2022

Ing.

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Diaphragmless shock tube with multiple air-operated valves

Inokuma

Maeda²,

Watanabe³

et al. 2022

Exp Fluids

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Statistical analysis of deformation of a shock wave propagating in a local turbulent region

2020

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Direct numerical simulation is performed for analyzing the interaction between a normal shock wave and turbulence. The shock wave is initially located in a quiescent fluid and propagates into a local turbulent region. This flow setup allows investigation of the initial transition and statistically steady stages of the interaction. Shock deformation is quantified using the local shock wave position. The root-mean-square (rms) fluctuation in the shock wave position increases during the initial stage of the interaction, for which the time interval divided by the integral time scale increases with Mt2/(Ms2−1), where Mt is a turbulent Mach number and Ms is a shock Mach number. In late time, the rms fluctuation in the shock wave position hardly depends on the propagation time and follows a power law, [Mt2/(Ms2−1)]0.46, whose exponent is similar to the power law exponent of the rms pressure-jump fluctuation reported in experimental studies. Fluctuations in the shock wave position have a Gaussian probability density function. The spectral analysis confirms that the length scale that characterizes shock wave deformation is the integral length scale of turbulence. The fluctuating shock wave position is correlated with dilatation of the shock wave, where the correlation coefficient increases with Mt/(Ms − 1). In addition, the shock wave that deforms backward tends to be stronger than average and vice versa. Mean pressure jumps across the shock wave are different between areas with forward and backward deformations. This difference increases with the rms fluctuation in the shock wave position and is well-represented as a function of Mt2/(Ms2−1).

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Statistical properties of spherical shock waves propagating through grid turbulence, turbulent cylinder wake, and laminar flow

Cited by 5 publications

References 25 publications

Characterization, Design Testing and Numerical Modeling of a Subsonic-Low Speed Wind Tunnel

Characterization, Design Testing and Numerical Modeling of a Subsonic-Low Speed Wind Tunnel

Diaphragmless shock tube with multiple air-operated valves

Statistical analysis of deformation of a shock wave propagating in a local turbulent region

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