Computations with the multiple reference frame technique: Flow and temperature fields downstream of an axial fan

Doğruöz, M. Barış; Shankaran, Gokul

doi:10.1080/10407782.2016.1277930

Cited by 20 publications

(4 citation statements)

References 21 publications

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“…53 Rotating frame motion has been applied in CFD work by early researchers. [54][55][56][57] The same strategy is recommended by Ansys ® for the simulations of rotating objects like analysis of helicopter rotor blades, propellers, fan blades and vortex interaction from helicopters rotor.…”

Section: Validation Of Pure Pitch Motion Using Unsteady Mesh Motionmentioning

confidence: 99%

Numerical estimation of longitudinal damping derivatives of a flying wing micro aerial vehicle

Shams

Shah

Shahzad

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part G:

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Longitudinal damping derivatives, [Formula: see text], of an aerial vehicle is important from an aerodynamic stability point of view. Experimental calculation of longitudinal damping derivatives using wind tunnel is not a cost-effective method; therefore, researchers have developed numerical solutions as an alternative. In this research, the longitudinal damping derivatives of a flying wing micro aerial vehicle (FWMAV) were calculated using numerical simulations by adopting pull-up maneuver and forced harmonic motion in pitch axis. Pull-up maneuver with four steady rotational rates was simulated to obtain pitch rate derivative, C mq. Combined derivative, [Formula: see text], was obtained by simulating forced harmonic motion of FWMAV around a mean angle of attack of 0° with amplitude of oscillation of ± 3° using four reduced frequencies (0.02, 0.03, 0.04, and 0.05). Unstructured surface and volume mesh was used in a spherical domain engulfed inside a large cuboid domain for moving reference frame strategy. Reynolds number taking mean aerodynamic chord as a reference length was 2.33 × 105. Spalart–Allmaras turbulence model was used. Pitch rate derivative, combined derivative, and acceleration derivative were found as − 0.03/rad, − 7.39/rad, and − 7.36/rad, respectively, by the use of a phase method at a reduced frequency of 0.03. During flight dynamic analysis, it was found that [Formula: see text] has a significant contribution on damping in short period mode with no effect on Phugoid mode. The research concluded that for tailless configurations, acceleration derivative [Formula: see text] can exist and can provide necessary damping in the longitudinal flight mode.

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Section: Validation Of Pure Pitch Motion Using Unsteady Mesh Motionmentioning

confidence: 99%

Numerical estimation of longitudinal damping derivatives of a flying wing micro aerial vehicle

Shams

Shah

Shahzad

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part G:

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“…This approach is currently mostly used in simulations of the cooling of electric components, due to their shorter development cycles. With increasing computational power more advanced models, such as the MRF, are becoming more common in those areas as well [2].…”

Section: Fan Modellingmentioning

confidence: 99%

“…The MRF approach is relatively simple to implement and suitable for steady state simulations, which makes it a computationally inexpensive method. This approach is often used in industrial applications, such as cooling of electrical components [1,2], ventilation [3,4], tidal current turbines [5,6] and automotive applications. In the automotive industry, areas of application are, e.g., the rotation of wheels [7] and of the fan for the cooling system.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the Multiple Reference Frame Approach for the Modelling of an Axial Cooling Fan

et al. 2019

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The modelling of rotating parts, such as axial fans, is one of the main challenges of current CFD simulations of industrial applications. Different methods are available, but the most commonly used is the multiple reference frame (MRF) method. This paper investigates how different flow properties, such as temperature, pressure and velocity, develop when passing through the MRF domain. The results are compared to the more physical rigid body motion (RBM) approach. It is found that the MRF method transports the upstream properties with the streamlines of the relative velocity from the upstream to the downstream interface. This leads to a non-physical rotation by an angle that is dependent on the length of the domain and the ratio between axial and tangential velocity in the MRF region. The temperature field is more affected than the flow field, since wake structures from upstream obstacles are destroyed due to the wake of the blades. Downstream structures affect the flow in the upstream region by an increase in static pressure, which causes the streamlines in the MRF zone to slow down. Depending on the size of the obstacle, this can cause substantial distortions in the upstream and downstream flow field.

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“…2) consisted of the hood and flail rotor, and the lower side of the hood was extended all the way to the ground [16]. In the calculations, the flail rotor was set in a rotary frame which was based on a multiple reference frame (MRF) model [22]. On account of the complexity of the tractor powered straw chopper geometry, tetrahedral mesh was generated to simulate internal flow field of the flail chopper model.…”

Section: Computational Domain and Mesh Generationmentioning

confidence: 99%

Numerical Simulation of the Effects of Design Parameters on the Performance of Tractor Powered Flail Choppers

Zhang

McHugh

et al. 2019

Computer and Computing Technologies in Agriculture XI

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Several design parameters of flail chopper were studied under a wide range of field and crop conditions to improve chopper performance. However, the effects of parameters on the internal straw flow characteristics that influence straw chopping and spreading performance are still unknown. In this paper, Computational Fluid Dynamics (CFD) were used to analyze the influence of three operating parameters (rotor speed, forward speed and hood clearance) and two structural parameters (fan blade number and flail tip clearance) on the flow characteristic in the tractor powered flail chopper. The pressure contours, maximum negative pressure and flow rate at the machine inlet were considered in the analysis of feeding performance. Velocity at 21 sampling points, area weighted and maximum velocities at the outlet were also considered for straw spreading performance. Streamlines from three sampling sections were analyzed for straw flow-ability.

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Computations with the multiple reference frame technique: Flow and temperature fields downstream of an axial fan

Cited by 20 publications

References 21 publications

Numerical estimation of longitudinal damping derivatives of a flying wing micro aerial vehicle

Numerical estimation of longitudinal damping derivatives of a flying wing micro aerial vehicle

Evaluation of the Multiple Reference Frame Approach for the Modelling of an Axial Cooling Fan

Numerical Simulation of the Effects of Design Parameters on the Performance of Tractor Powered Flail Choppers

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