An investigation on the body force modeling in a lattice Boltzmann BGK simulation of generalized Newtonian fluids

2014 ◽  
Vol 415 ◽  
pp. 315-332 ◽  
Author(s):  
Somayeh Farnoush ◽  
Mehrdad T. Manzari
Keyword(s):  
Lattice Boltzmann ◽  
Body Force ◽  
The Body ◽  
Newtonian Fluids ◽  
Generalized Newtonian Fluids ◽  
Force Modeling

A Review of Inlet-Fan Coupling Methodologies

2017 ◽  
Author(s):  
Benjamin Godard ◽  
Edouard De Jaeghere ◽  
Nabil Ben Nasr ◽  
Julien Marty ◽  
Raphael Barrier ◽  
...  
Keyword(s):  
Experimental Data ◽  
Industrial Design ◽  
Body Force ◽  
The Body ◽  
Source Terms ◽  
Force Modeling ◽  
Actuator Disc ◽  
Flow Deviation ◽  
New Challenges ◽  
Bypass Ratio

With the rise of ultra high bypass ratio turbofan and shorter and slimmer inlet geometries compared to classical architectures, designers face new challenges as nacelle and fan design cannot anymore be addressed independently. This paper reviews CFD methods developed to simulate inlet-fan interactions and suitable for industrial design cycles. In addition to the reference isolated fan and nacelle models, the methodologies evaluated in this study consist of two fan modeling approaches, an actuator disc and body-force source terms. The configuration is a modern turbofan with a high bypass ratio under cross-wind. Results are compared to experimental data. As to be predicted, the body-force modeling approach enables early inlet reattachment. In addition, it provides a representative flow deviation across the fan zone which enables performance and stability assessments.

scholarly journals Body Force Modeling of the Aerodynamics of a Low-Speed Fan under Distorted Inflow †

2019 ◽  
Vol 4 (3) ◽  
pp. 29 ◽  
Author(s):  
Emmanuel Benichou ◽  
Guillaume Dufour ◽  
Yannick Bousquet ◽  
Nicolas Binder ◽  
Aurélie Ortolan ◽  
...  
Keyword(s):  
Body Force ◽  
Engine Performance ◽  
The Body ◽  
Navier Stokes ◽  
Complex Flows ◽  
Low Speed ◽  
Force Modeling ◽  
Cooling Fan ◽  
Computational Fluid Dynamics Cfd ◽  
Turbomachinery Design

New propulsive concepts, such as boundary layer ingestion, involve stronger interactions between the engine and its environment, and are thus more complex flows compared to classical architectures. Usual turbomachinery design tools are inadequate, and new numerical methodologies are needed to accurately predict the engine performance with affordable CPU resources. The present paper examines the relevance of a reduced-order modeling approach—the body force modeling (BFM) method—for a low-speed cooling fan with inflow distortion. The formulation itself accounts for the blade metal blockage and compressibility effects, and it relies on a semiempirical loss model, independent of computational fluid dynamics (CFD) calibration. The BFM results obtained in the present work are assessed against full-annulus unsteady Reynolds-averaged Navier-Stokes (URANS) results and experiments. The comparison shows that the BFM approach successfully quantifies the fan stage performance. Furthermore, the distortion transfer across the stage is examined and the flow patterns observed are found to be the same as in the URANS results and in the measurements. Hence, this methodology, coming at a low CPU cost, is well-adapted to the early design phase of an innovative propulsion system.

Assessment of Body Force Methodologies for the Analysis of Intake-Fan Aerodynamic Interactions

2016 ◽  
Author(s):  
William Thollet ◽  
Guillaume Dufour ◽  
Xavier Carbonneau ◽  
Florian Blanc
Keyword(s):  
Body Force ◽  
The Body ◽  
Test Cases ◽  
Validation Data ◽  
Turbofan Engines ◽  
Force Modeling ◽  
The Cost ◽  
Engine Components ◽  
Bypass Ratio ◽  
Numerical Strategy

With the advent of high bypass ratio turbofan engines of increasing size, new nacelle designs with shorter air intakes have to be considered, creating new aerodynamic interactions with the fan. This paper focuses on a numerical strategy known as Body Force Modeling, in which engine components are modeled and taken into account using source terms in the RANS equation. This approach allows to simulate these interactions with an accuracy comparable to full 360° unsteady simulations, but at a fraction of the cost. Different formulations for the body forces are proposed and applied to different nacelle test cases of varying intake length. Using full annulus unsteady computations as validation data, it is shown that the body force approach allows to capture inlet design effects on in-plane forces and on nacelle flow separation.

scholarly journals A high-fidelity body-force modeling approach for plasma-based flow control simulations

2021 ◽  
Vol 33 (3) ◽  
pp. 037115
Author(s):  
Di Chen ◽  
Kengo Asada ◽  
Satoshi Sekimoto ◽  
Kozo Fujii ◽  
Hiroyuki Nishida
Keyword(s):  
Flow Control ◽  
Body Force ◽  
High Fidelity ◽  
Modeling Approach ◽  
Force Modeling

scholarly journals Computational Modeling of Vortex Generators for Turbomachinery

2002 ◽  
Author(s):  
R. V. Chima
Keyword(s):  
Computational Models ◽  
Body Force ◽  
Secondary Flows ◽  
The Body ◽  
Vortex Generators ◽  
Force Model ◽  
Suction Surface ◽  
Near Surface ◽  
Compressor Rotor ◽  
Surface Particle

In this work computational models were developed and used to investigate applications of vortex generators (VGs) to turbomachinery. The work was aimed at increasing the efficiency of compressor components designed for the NASA Ultra Efficient Engine Technology (UEET) program. Initial calculations were used to investigate the physical behavior of VGs. A parametric study of the effects of VG height was done using 3-D calculations of isolated VGs. A body force model was developed to simulate the effects of VGs without requiring complicated grids. The model was calibrated using 2-D calculations of the VG vanes and was validated using the 3-D results. Then three applications of VGs to a compressor rotor and stator were investigated: 1. The results of the 3-D calculations were used to simulate the use of small casing VGs used to generate rotor preswirl or counterswirl. Computed performance maps were used to evaluate the effects of VGs. 2. The body force model was used to simulate large partspan splitters on the casing ahead of the stator. Computed loss buckets showed the effects of the VGs. 3. The body force model was also used to investigate the use of tiny VGs on the stator suction surface for controlling secondary flows. Near-surface particle traces and exit loss profiles were used to evaluate the effects of the VGs.

Stresses and Displacements in a Rotating Conical Shell

1943 ◽  
Vol 10 (2) ◽  
pp. A53-A61
Author(s):  
J. L. Meriam
Keyword(s):  
Conical Shell ◽  
Body Force ◽  
Theory Of Elasticity ◽  
Common Type ◽  
The Body ◽  
Surface Loading ◽  
Thin Walled Structures ◽  
Special Cases ◽  
Engineering Problems ◽  
Rotating Conical Shell

Abstract The analysis of shells is an important subdivision of the general theory of elasticity, and its application is useful in the solution of engineering problems involving thin-walled structures. A common type of shell is one which possesses symmetry with respect to an axis of revolution. A theory for such shells has been developed by various investigators (1, 2, 3, 6) and applied to a few simple cases such as the cylindrical, spherical, and conical shapes. Boundary conditions, for the most part, have been simple static ones, and conditions of surface loading have been included in certain special cases. This paper extends the theory of axially symmetrical shells by including the body force of rotation about the axis and applies the results to the rotating conical shell. The analysis follows a pattern established by several investigators (1, 2, 3, 6) and for this reason is abbreviated to a considerable extent. Only where the inclusion of the body force makes elucidation advisable or where a slightly different method of approach is used are the steps presented in more detail.

Rack Level Modeling of Air Flow Through Perforated Tile in a Data Center

2012 ◽  
Author(s):  
Vaibhav K. Arghode ◽  
Pramod Kumar ◽  
Yogendra Joshi ◽  
Thomas S. Weiss ◽  
Gary Meyer
Keyword(s):  
Data Center ◽  
Body Force ◽  
Air Flow ◽  
The Body ◽  
Physical Models ◽  
Cfd Modeling ◽  
Computational Time ◽  
Force Model ◽  
Flow Through ◽  
Tile Surface

Effective air flow distribution through perforated tiles is required to efficiently cool servers in a raised floor data center. We present detailed computational fluid dynamics (CFD) modeling of air flow through a perforated tile and its entrance to the adjacent server rack. The realistic geometrical details of the perforated tile, as well as of the rack are included in the model. Generally models for air flow through perforated tiles specify a step pressure loss across the tile surface, or porous jump model based on the tile porosity. An improvement to this includes a momentum source specification above the tile to simulate the acceleration of the air flow through the pores, or body force model. In both of these models geometrical details of tile such as pore locations and shapes are not included. More details increase the grid size as well as the computational time. However, the grid refinement can be controlled to achieve balance between the accuracy and computational time. We compared the results from CFD using geometrical resolution with the porous jump and body force model solution as well as with the measured flow field using Particle Image Velocimetry (PIV) experiments. We observe that including tile geometrical details gives better results as compared to elimination of tile geometrical details and specifying physical models across and above the tile surface. A modification to the body force model is also suggested and improved results were achieved.

The Effect of Blade Count on Body Force Model Performance for Axial Fans

2020 ◽  
Author(s):  
Palak Saini ◽  
Jeff Defoe
Keyword(s):  
Body Force ◽  
Computational Cost ◽  
Model Performance ◽  
Aircraft Engine ◽  
The Body ◽  
Force Model ◽  
Cooling Flows ◽  
Cooling Fans ◽  
Axial Fans ◽  
Spanwise Flow

Abstract Body force models enable inexpensive numerical simulations of turbomachinery. The approach replaces the blades with sources of momentum/energy. Such models capture a “smeared out” version of the blades’ effect on the flow, reducing computational cost. The body force model used in this paper has been widely used in aircraft engine applications. Its implementation for low speed, low solidity (few blades) turbomachines, such as automotive cooling fans, enables predictions of cooling flows and component temperatures without calibrated fan curves. Automotive cooling fans tend to have less than 10 blades, which is approximately 50% of blade counts for modern jet engine fans. The effect this has on the body force model predictions is unknown and the objective of this paper is to quantify how varying blade count affects the accuracy of the predictions for both uniform and non-uniform inflow. The key findings are that reductions in blade metal blockage combined with spanwise flow redistribution drives the body force model to more accurately predict work coefficient as the blade count decreases, and that reducing the number of blades is found to have negligible impacts on upstream influence and distortion transfer in non-uniform inflow until extremely low blade counts (such as 2) are applied.

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