pith. sign in

arxiv: 2606.31707 · v1 · pith:QPJNOPFNnew · submitted 2026-06-30 · ⚛️ physics.flu-dyn

Mean-Flow Adjoint Sensitivity Analysis of Unsteady Flow Around Porous Cylinders Using a Homogenized Lattice Boltzmann Method

Pith reviewed 2026-07-01 03:10 UTC · model grok-4.3

classification ⚛️ physics.flu-dyn
keywords mean-flow adjointlattice Boltzmann methodporous cylindersBrinkman penalizationlarge eddy simulationautomatic differentiationsensitivity analysisturbulent flows
0
0 comments X

The pith

A mean-flow adjoint framework computes sensitivities for unsteady and turbulent flows around porous cylinders in lattice Boltzmann simulations.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper presents a mean-flow adjoint sensitivity analysis framework for unsteady flows around porous cylinders using the homogenized lattice Boltzmann method. Solid structures are modeled as local porous media with Brinkman penalization. The framework is tested on drag and energy dissipation objectives across steady laminar, unsteady, and turbulent regimes at Reynolds number 3900. For the turbulent case, automatic differentiation automatically generates adjoint kernels that include subgrid-scale turbulence models for large eddy simulations. This circumvents manual derivation and allows comparison to the frozen turbulence assumption while addressing memory and stability issues in chaotic flows.

Core claim

The mean-flow adjoint sensitivity analysis framework enables computation of gradients for design and control in unsteady and turbulent regimes by using the homogenized lattice Boltzmann method with Brinkman penalization for porous cylinders and automatic differentiation to incorporate subgrid-scale models in the adjoint equations.

What carries the argument

Mean-flow adjoint formulation with automatic differentiation for adjoint kernels containing subgrid-scale turbulence models in the homogenized lattice Boltzmann method.

If this is right

  • Adjoint gradients can be obtained for unsteady flows without prohibitive memory requirements from checkpointing.
  • Direct comparison between automatic differentiation-based adjoints and frozen turbulence assumption is possible in turbulent large eddy simulations.
  • The approach extends to turbulent flow regimes at Reynolds number 3900 around porous media.
  • Objective functionals such as drag and energy dissipation can be analyzed in transitioning flow regimes.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • Applying this to optimization problems could allow automated design of porous flow control devices.
  • Similar automatic differentiation techniques might extend mean-flow adjoints to other turbulence modeling approaches in fluid simulations.
  • The method could be tested on different objective functionals or geometries to broaden its applicability.

Load-bearing premise

The mean-flow adjoint formulation remains accurate and stable for the chosen objective functionals when applied to unsteady and turbulent regimes around porous media modeled by Brinkman penalization.

What would settle it

A direct numerical comparison showing that the mean-flow adjoint gradients diverge significantly from those obtained by finite differences or other verification methods in the turbulent case at Re = 3900 would falsify the approach.

Figures

Figures reproduced from arXiv: 2606.31707 by Adrian Kummerl\"ander, Fedor Bukreev, Johannes L. Grafen, Mathias J. Krause, Shota Ito.

Figure 1
Figure 1. Figure 1: Validation of the drag force for the cylinder modeled as a porous medium by HLBM. [PITH_FULL_IMAGE:figures/full_fig_p009_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: Schematic illustration of the simulation setup in 2D with the used domain sizes and cylinder positions. [PITH_FULL_IMAGE:figures/full_fig_p010_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: Validation of the adjoint gradients for the different objective functionals. The surface gradients are compared for [PITH_FULL_IMAGE:figures/full_fig_p011_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: Schematic illustration of the simulation setup in 3D with the used domain sizes and cylinder positions. [PITH_FULL_IMAGE:figures/full_fig_p012_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: Validation of the adjoint gradients for the different objective functionals. The surface gradients are compared for [PITH_FULL_IMAGE:figures/full_fig_p013_5.png] view at source ↗
Figure 6
Figure 6. Figure 6: Mean-flow adjoint of unsteady laminar 2D cylinder flow at [PITH_FULL_IMAGE:figures/full_fig_p013_6.png] view at source ↗
Figure 7
Figure 7. Figure 7: Contour plot of the Q-criterion at Q = 2 for the primal velocity. deliver dedicated turbulence statistics evaluation for the current cylinder flow, as the primal model has been validated in the turbulent regime against experimental results in several previous works [17, 18, 37, 38, 52]. The simulation setup for the turbulent case is identical to Sec. 5.2.2 as sketched in [PITH_FULL_IMAGE:figures/full_fig_… view at source ↗
Figure 8
Figure 8. Figure 8: Comparison of the adjoint solutions for the adjoint HHRR-LES model and the FTA. [PITH_FULL_IMAGE:figures/full_fig_p015_8.png] view at source ↗
Figure 9
Figure 9. Figure 9: Surface gradients computed by the mean-flow adjoint approach for the turbulent cylinder case at [PITH_FULL_IMAGE:figures/full_fig_p015_9.png] view at source ↗
read the original abstract

Adjoint-based sensitivity analysis is an indispensable tool for large-scale fluid-dynamic design and distributed control problems, yet its application to unsteady and turbulent flows is frequently hindered by the prohibitive memory footprint of transient checkpointing and the divergence of gradients in chaotic regimes. To address these computational bottlenecks, this paper presents a mean-flow adjoint sensitivity analysis framework for unsteady flows around porous cylinders using the homogenized lattice Boltzmann method (HLBM). Within this framework, solid structures are efficiently modeled as local porous media utilizing a Brinkman penalization approach. We systematically investigate HLBM-based adjoint gradients for drag and energy dissipation objective functionals, transitioning from steady laminar to unsteady, and finally to turbulent flow regimes. For the turbulent case at Re = 3900, a proof-of-concept is conducted where the framework relies on automatic differentiation to automatically generate adjoint kernels containing subgrid-scale (SGS) turbulence models for large eddy simulations (LES), circumventing manual derivation and allowing for a direct comparison against the frozen turbulence assumption (FTA).

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

1 major / 1 minor

Summary. The manuscript presents a mean-flow adjoint sensitivity analysis framework for unsteady flows around porous cylinders using the homogenized lattice Boltzmann method (HLBM) with Brinkman penalization for solid modeling. It systematically examines HLBM-based adjoint gradients for drag and energy-dissipation functionals across steady laminar, unsteady, and turbulent regimes, with a proof-of-concept at Re=3900 that employs automatic differentiation to generate adjoint kernels incorporating subgrid-scale (SGS) turbulence models for LES, enabling comparison to the frozen turbulence assumption (FTA).

Significance. If the mean-flow adjoint formulation proves accurate and stable for the chosen functionals under unsteady/turbulent conditions with Brinkman forcing and SGS closures, the framework would offer a practical route to adjoint-based design and control in porous-media flows without manual derivation of adjoint SGS terms. The automatic differentiation approach for including SGS models is a clear methodological strength that could generalize beyond the specific HLBM implementation.

major comments (1)
  1. [Abstract (transitioning regimes paragraph)] Abstract (paragraph on transitioning regimes and Re=3900 proof-of-concept): the central claim that the mean-flow adjoint remains accurate and stable when SGS models are included via AD is load-bearing for the extension to turbulent regimes, yet no quantitative consistency checks (e.g., gradient verification against finite differences or discrete adjoint residual norms) or stability metrics are reported for the drag or energy-dissipation functionals; this leaves open whether the mean-flow averaging plus homogenized porous forcing introduces uncontrolled inconsistencies with the SGS closure.
minor comments (1)
  1. [Abstract] The abstract supplies no equations, error bars, or comparison metrics, making it difficult to assess the numerical implementation details of the HLBM adjoint or the specific objective functionals used.

Simulated Author's Rebuttal

1 responses · 0 unresolved

We thank the referee for the detailed and constructive report. The single major comment is addressed below. We agree that additional quantitative validation strengthens the turbulent-regime claims and will revise the manuscript accordingly.

read point-by-point responses
  1. Referee: [Abstract (transitioning regimes paragraph)] Abstract (paragraph on transitioning regimes and Re=3900 proof-of-concept): the central claim that the mean-flow adjoint remains accurate and stable when SGS models are included via AD is load-bearing for the extension to turbulent regimes, yet no quantitative consistency checks (e.g., gradient verification against finite differences or discrete adjoint residual norms) or stability metrics are reported for the drag or energy-dissipation functionals; this leaves open whether the mean-flow averaging plus homogenized porous forcing introduces uncontrolled inconsistencies with the SGS closure.

    Authors: We agree that quantitative consistency checks are necessary to support the central claim for turbulent regimes. The Re=3900 case is presented as a proof-of-concept demonstrating that AD-generated adjoint kernels containing the SGS model can be obtained without manual derivation and that the resulting mean-flow sensitivities differ from the FTA. However, the manuscript does not report finite-difference gradient verifications or adjoint residual norms for this case. In the revised manuscript we will add (i) finite-difference verification of the drag-functional gradient for a small number of porous parameters at Re=3900 and (ii) discrete adjoint residual norms to quantify stability. These results will be placed in a new validation subsection of the turbulent-flow results and referenced from the abstract. revision: yes

Circularity Check

0 steps flagged

No circularity detected in derivation chain

full rationale

The paper describes a mean-flow adjoint sensitivity framework for HLBM with Brinkman penalization, using automatic differentiation to generate adjoint kernels that include SGS turbulence models for the Re=3900 LES case. No load-bearing step reduces by construction to its inputs: the AD-generated adjoints are presented as a direct computational extension of the forward operator rather than a fitted or renamed quantity, and no self-citation chain is invoked to justify uniqueness or an ansatz. The transition from laminar to turbulent regimes is handled by standard numerical methods without evidence of self-definitional closure or prediction-by-fit. The framework remains self-contained against external benchmarks such as discrete adjoint consistency checks and frozen-turbulence comparisons.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

Abstract-only review; no explicit free parameters, axioms, or invented entities stated. Assumes standard fluid equations and penalization model hold for the regimes described.

pith-pipeline@v0.9.1-grok · 5727 in / 1067 out tokens · 39291 ms · 2026-07-01T03:10:20.932679+00:00 · methodology

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Reference graph

Works this paper leans on

54 extracted references · 38 canonical work pages · 1 internal anchor

  1. [1]

    Cheylan, G

    I. Cheylan, G. Fritz, D. Ricot, P. Sagaut, Shape Optimization Using the Adjoint Lattice Boltzmann Method for Aerodynamic Applications, AIAA Journal 57 (7) (2019) 2758–2773, publisher: American Institute of Aeronautics and Astronautics _eprint: https://doi.org/10.2514/1.J057955.doi:10.2514/ 1.J057955. URLhttps://doi.org/10.2514/1.J057955

  2. [2]

    Jalali Khouzani, R

    H. Jalali Khouzani, R. Kamali-Moghadam, Airfoil inverse design based on laminar compressible adjoint lattice Boltzmann method, International Journal for Numerical Methods in Fluids 95 (8) (2023) 1197– 1219, _eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/fld.5192.doi:10.1002/fld.5192. URLhttps://onlinelibrary.wiley.com/doi/abs/10.1002/fld.5192

  3. [3]

    Stück, Adjoint Navier-Stokes methods for hydrodynamic shape optimisation, Technische Universität Hamburg, 2012

    A. Stück, Adjoint Navier-Stokes methods for hydrodynamic shape optimisation, Technische Universität Hamburg, 2012

  4. [4]

    Dugast, Y

    F. Dugast, Y. Favennec, C. Josset, Y. Fan, L. Luo, Topology optimization of thermal fluid flows with an adjoint Lattice Boltzmann Method, Journal of Computational Physics 365 (2018) 376–404. doi:10.1016/j.jcp.2018.03.040. URLhttps://www.sciencedirect.com/science/article/pii/S0021999118302067

  5. [5]

    M. J. Krause, G. Thäter, V. Heuveline, Adjoint-based fluid flow control and optimisation with lattice Boltzmann methods, Computers & Mathematics with Applications 65 (6) (2013) 945–960.doi:10. 1016/j.camwa.2012.08.007. URLhttps://www.sciencedirect.com/science/article/pii/S0898122112005421

  6. [6]

    Łaniewski-Wołłk, Ł. and Rokicki, J., Adjoint Lattice Boltzmann for topology optimization on multi- GPU architecture, Computers & Mathematics with Applications 71 (3) (2016) 833–848.doi:10.1016/ j.camwa.2015.12.043. URLhttps://www.sciencedirect.com/science/article/pii/S0898122115006215

  7. [7]

    S. Ito, J. Jeßberger, S. Simonis, F. Bukreev, A. Kummerländer, A. Zimmermann, G. Thäter, G. R. Pesch, J. Thöming, M. J. Krause, Identification of reaction rate parameters from uncertain spatially distributedconcentrationdatausinggradient-basedPDEconstrainedoptimization, Computers&Math- ematics with Applications 167 (2024) 249–263.doi:10.1016/j.camwa.2024....

  8. [8]

    C. Chen, K. Yaji, T. Yamada, K. Izui, S. Nishiwaki, Local-in-time adjoint-based topology optimization of unsteady fluid flows using the lattice Boltzmann method, Mechanical Engineering Journal 4 (3) (2017) 17–00120, num Pages: 17-00120.doi:10.1299/mej.17-00120

  9. [9]

    S. Ito, A. Zimmermann, J. Jeßberger, S. Simonis, A. Kummerländer, F. Bukreev, J. Thöming, G. Pesch, M. J. Krause, Geometry reconstruction from magnetic resonance velocimetry measurements via solving an inverse fluid flow problem, Journal of Computational Physics (2026) 115151doi:10.1016/j.jcp. 2026.115151. URLhttps://www.sciencedirect.com/science/article/...

  10. [10]

    Borrvall, J

    T. Borrvall, J. Petersson, Topology optimization of fluids in stokes flow, International Journal for Numerical Methods in Fluids 41 (1) (2003) 77–107.arXiv:https://onlinelibrary.wiley.com/doi/ pdf/10.1002/fld.426,doi:https://doi.org/10.1002/fld.426. URLhttps://onlinelibrary.wiley.com/doi/abs/10.1002/fld.426

  11. [11]

    Pingen, A

    G. Pingen, A. Evgrafov, K. Maute, Adjoint parameter sensitivity analysis for the hydrodynamic lattice Boltzmann method with applications to design optimization, Computers & Fluids 38 (4) (2009) 910– 923.doi:10.1016/j.compfluid.2008.10.002. URLhttps://www.sciencedirect.com/science/article/pii/S0045793008001989 20

  12. [12]

    K. Yaji, T. Yamada, M. Yoshino, T. Matsumoto, K. Izui, S. Nishiwaki, Topology optimization in thermal-fluid flow using the lattice Boltzmann method, Journal of Computational Physics 307 (2016) 355–377.doi:10.1016/j.jcp.2015.12.008. URLhttps://www.sciencedirect.com/science/article/pii/S0021999115008244

  13. [13]

    G. Liu, M. Geier, Z. Liu, M. Krafczyk, T. Chen, Discrete adjoint sensitivity analysis for fluid flow topology optimization based on the generalized lattice Boltzmann method, Computers & Mathematics with Applications 68 (10) (2014) 1374–1392.doi:10.1016/j.camwa.2014.09.002. URLhttps://www.sciencedirect.com/science/article/pii/S0898122114004507

  14. [14]

    Mohammadi, O

    B. Mohammadi, O. Pironneau, Shape optimization in fluid mechanics, Annu. Rev. Fluid Mech. 36 (1) (2004) 255–279

  15. [15]

    K. Yaji, T. Yamada, M. Yoshino, T. Matsumoto, K. Izui, S. Nishiwaki, Topology optimization using the lattice boltzmann method incorporating level set boundary expressions, Journal of Computational Physics 274 (2014) 158–181.doi:https://doi.org/10.1016/j.jcp.2014.06.004. URLhttps://www.sciencedirect.com/science/article/pii/S0021999114004112

  16. [16]

    M. J. Krause, A. Kummerländer, S. J. Avis, H. Kusumaatmaja, D. Dapelo, F. Klemens, M. Gaedtke, N. Hafen, A. Mink, R. Trunk, J. E. Marquardt, M.-L. Maier, M. Haussmann, S. Simonis, OpenLB—Open source lattice Boltzmann code, Computers & Mathematics with Applications 81 (2021) 258–288.doi:10.1016/j.camwa.2020.04.033. URLhttps://www.sciencedirect.com/science/...

  17. [17]

    Kummerländer, B

    A. Kummerländer, B. Tur, M. Haase, F. Bukreev, M. Döllinger, M. J. Krause, S. Kniesburges, Efficient fluid structure interaction simulation of vocal fold oscillations using a homogenized Lattice Boltzmann Method, Computer Methods in Applied Mechanics and Engineering 457 (2026) 119009.doi:10.1016/ j.cma.2026.119009. URLhttps://www.sciencedirect.com/science...

  18. [18]

    Kummerländer, S

    A. Kummerländer, S. Ito, M. Schecher, D. Dapelo, S. Simonis, M. J. Krause, F. Bukreev, Ef- ficient wall-modelled large eddy simulation of rotors using homogenized lattice Boltzmann meth- ods, International Journal of Numerical Methods for Heat & Fluid Flow 36 (7) (2026) 2649–2673. doi:10.1108/HFF-09-2025-0724. URLhttps://doi.org/10.1108/HFF-09-2025-0724

  19. [19]

    S. Ito, A. Kummerländer, J. Jeßberger, J. L. Grafen, E. Öz, N. R. Gauger, M. Sagebaum, M. J. Krause, Generation of efficient adjoint lattice Boltzmann methods with algorithmic differentiation (Apr. 2026). doi:10.2139/ssrn.6505987. URLhttps://papers.ssrn.com/abstract=6505987

  20. [20]

    Klemens, B

    F. Klemens, B. Förster, M. Dorn, G. Thäter, M. J. Krause, Solving fluid flow domain identification problems with adjoint lattice Boltzmann methods, Computers & Mathematics with Applications 79 (1) (2020) 17–33.doi:10.1016/j.camwa.2018.07.010. URLhttps://www.sciencedirect.com/science/article/pii/S0898122118303754

  21. [21]

    M. J. Krause, F. Klemens, T. Henn, R. Trunk, H. Nirschl, Particle flow simulations with homogenised lattice boltzmann methods, Particuology 34 (2017) 1–13.doi:https://doi.org/10.1016/j.partic. 2016.11.001. URLhttps://www.sciencedirect.com/science/article/pii/S167420011730041X

  22. [22]

    Nørgaard, O

    S. Nørgaard, O. Sigmund, B. Lazarov, Topology optimization of unsteady flow problems using the lattice boltzmann method, Journal of Computational Physics 307 (2016) 291–307.doi:https://doi. org/10.1016/j.jcp.2015.12.023. URLhttps://www.sciencedirect.com/science/article/pii/S0021999115008426 21

  23. [23]

    Meliga, E

    P. Meliga, E. Boujo, G. Pujals, F. Gallaire, Sensitivity of aerodynamic forces in laminar and turbulent flow past a square cylinder, Physics of Fluids 26 (10) (2014) 104101.arXiv:https://pubs.aip.org/ aip/pof/article-pdf/doi/10.1063/1.4896941/13799256/104101_1_online.pdf,doi:10.1063/1. 4896941. URLhttps://doi.org/10.1063/1.4896941

  24. [24]

    N. K. Yamaleev, B. Diskin, E. J. Nielsen, Local-in-time adjoint-based method for design optimization of unsteady flows, Journal of Computational Physics 229 (14) (2010) 5394–5407.doi:https://doi. org/10.1016/j.jcp.2010.03.045. URLhttps://www.sciencedirect.com/science/article/pii/S0021999110001646

  25. [25]

    K. Yaji, M. Ogino, C. Chen, K. Fujita, Large-scale topology optimization incorporating local-in-time adjoint-based method for unsteady thermal-fluid problem, Structural and Multidisciplinary Optimiza- tion 58 (2) (2018) 817–822

  26. [26]

    P. J. Blonigan, Q. Wang, E. J. Nielsen, B. Diskin, Least-squares shadowing sensitivity analysis of chaotic flow around a two-dimensional airfoil, AIAA Journal 56 (2) (2018) 658–672.arXiv:https: //doi.org/10.2514/1.J055389,doi:10.2514/1.J055389. URLhttps://doi.org/10.2514/1.J055389

  27. [27]

    A. C. Marta, S. Shankaran, On the handling of turbulence equations in rans adjoint solvers, Computers & Fluids 74 (2013) 102–113.doi:https://doi.org/10.1016/j.compfluid.2013.01.012. URLhttps://www.sciencedirect.com/science/article/pii/S0045793013000303

  28. [28]

    E. M. Papoutsis-Kiachagias, K. C. Giannakoglou, Continuous adjoint methods for turbulent flows, ap- plied to shape and topology optimization: industrial applications, Archives of Computational Methods in Engineering 23 (2) (2016) 255–299

  29. [29]

    Schramm, B

    M. Schramm, B. Stoevesandt, J. Peinke, Optimization of airfoils using the adjoint approach and the influence of adjoint turbulent viscosity, Computation 6 (1) (2018).doi:10.3390/computation6010005. URLhttps://www.mdpi.com/2079-3197/6/1/5

  30. [30]

    R. P. Dwight, J. Brezillon, Effect of approximations of the discrete adjoint on gradient-based op- timization, AIAA Journal 44 (12) (2006) 3022–3031.arXiv:https://doi.org/10.2514/1.21744, doi:10.2514/1.21744. URLhttps://doi.org/10.2514/1.21744

  31. [31]

    Simonis, N

    S. Simonis, N. Hafen, J. Jeßberger, D. Dapelo, G. Thäter, M. J. Krause, Homogenized lattice boltzmann methods for fluid flow through porous media–part i: kinetic model derivation, ESAIM: Mathematical Modelling and Numerical Analysis 59 (2) (2025) 789–813

  32. [32]

    P. L. Bhatnagar, E. P. Gross, M. Krook, A model for collision processes in gases. i. small amplitude processes in charged and neutral one-component systems, Physical Review 94 (3) (1954) 511–525. doi:10.1103/PhysRev.94.511

  33. [33]

    Y. H. Qian, D. D’Humières, P. Lallemand, Lattice bgk models for navier-stokes equation, Europhysics Letters (EPL) 17 (6) (1992) 479–484.doi:10.1209/0295-5075/17/6/001

  34. [34]

    M. A. Spaid, F. R. Phelan Jr, Lattice boltzmann methods for modeling microscale flow in fibrous porous media, Physics of fluids 9 (9) (1997) 2468–2474

  35. [35]

    Krüger, H

    T. Krüger, H. Kusumaatmaja, A. Kuzmin, O. Shardt, G. Silva, E. M. Viggen, The Lattice Boltzmann Method: Principles and Practice, Graduate Texts in Physics, Springer International Publishing and Imprint and Springer, Cham, 2017

  36. [36]

    Smagorinsky, General circulation experiments with the primitive equations: I

    J. Smagorinsky, General circulation experiments with the primitive equations: I. the basic experiment, Monthly weather review 91 (3) (1963) 99–164. 22

  37. [37]

    Recursive regularization step for high-order lattice Boltzmann methods

    C. Coreixas, G. Wissocq, G. Puigt, J.-F. Boussuge, P. Sagaut, Recursive regularization step for high- order lattice boltzmann methods, arXiv preprint arXiv:1704.04413 (2017)

  38. [38]

    Jacob, O

    J. Jacob, O. Malaspinas, P. Sagaut, A new hybrid recursive regularised bhatnagar–gross–krook collision model for lattice boltzmann method-based large eddy simulation, Journal of Turbulence 19 (11-12) (2018) 1051–1076

  39. [39]

    Malaspinas, P

    O. Malaspinas, P. Sagaut, Consistent subgrid scale modelling for lattice boltzmann methods, Journal of Fluid Mechanics 700 (2012) 514–542.doi:10.1017/jfm.2012.155

  40. [40]

    M. D. Gunzburger, Perspectives in Flow Control and Optimization, Society for Industrial and Applied Mathematics, 2002.arXiv:https://epubs.siam.org/doi/pdf/10.1137/1.9780898718720,doi:10. 1137/1.9780898718720. URLhttps://epubs.siam.org/doi/abs/10.1137/1.9780898718720

  41. [41]

    A. J. C. Ladd, Numerical simulations of particulate suspensions via a discretized Boltzmann equation. Part 1. Theoretical foundation 271 285–309.doi:10.1017/S0022112094001771. URLhttps://www.cambridge.org/core/product/identifier/S0022112094001771/type/ journal_article

  42. [42]

    A. J. C. Ladd, Numerical simulations of particulate suspensions via a discretized Boltzmann equation. Part 2. Numerical results 271 311–339.doi:10.1017/S0022112094001783. URLhttps://www.cambridge.org/core/product/identifier/S0022112094001783/type/ journal_article

  43. [43]

    Onorato, A

    M. Onorato, A. Costelli, A. Garrone, L. Viassone, Experimental analysis of vehicle wakes, Journal of Wind Engineering and Industrial Aerodynamics 22 (2) (1986) 317–330, special Issue 6th Colloquium on Industrial Aerodynamics Vehicle Aerodynamics.doi:https://doi.org/10.1016/0167-6105(86) 90094-2. URLhttps://www.sciencedirect.com/science/article/pii/0167610...

  44. [44]

    Wang, J.-R

    C.-H. Wang, J.-R. Ho, A lattice boltzmann approach for the non-newtonian effect in the blood flow, Computers & Mathematics with Applications 62 (2011) 75–86.doi:10.1016/j.camwa.2011.04.051

  45. [45]

    Schäfer, S

    M. Schäfer, S. Turek, F. Durst, E. Krause, R. Rannacher, Benchmark computations of laminar flow around a cylinder, in: Flow simulation with high-performance computers II: DFG priority research programme results 1993–1995, Springer, 1996, pp. 547–566

  46. [46]

    Bouzidi, M

    M. Bouzidi, M. Firdaouss, P. Lallemand, Momentum transfer of a boltzmann-lattice fluid with bound- aries, Physics of fluids 13 (11) (2001) 3452–3459

  47. [47]

    S. K. Nadarajah, The discrete adjoint approach to aerodynamic shape optimization, stanford university, 2003

  48. [48]

    F. H. Abernathy, R. E. Kronauer, The formation of vortex streets, Journal of Fluid Mechanics 13 (1) (1962) 1–20

  49. [49]

    Wang, J.-H

    Q. Wang, J.-H. Gao, The drag-adjoint field of a circular cylinder wake at reynolds numbers 20, 100 and 500, Journal of Fluid Mechanics 730 (2013) 145–161.doi:10.1017/jfm.2013.323

  50. [50]

    B. N. Rajani, A. Kandasamy, S. Majumdar, Les of flow past circular cylinder at re = 3900, Journal of Applied Fluid Mechanics 9 (3) (2016) 1421–1435.arXiv:https://www.jafmonline.net/article_ 1718_fc6709bfdf0572f183c1a84ce5276e96.pdf,doi:10.18869/acadpub.jafm.68.228.24178. URLhttps://www.jafmonline.net/article_1718.html 23

  51. [51]

    Franke, W

    J. Franke, W. Frank, Large eddy simulation of the flow past a circular cylinder at red=3900, Journal of Wind Engineering and Industrial Aerodynamics 90 (10) (2002) 1191–1206, 3rd European-African Conference on Wind Engineering.doi:https://doi.org/10.1016/S0167-6105(02)00232-5. URLhttps://www.sciencedirect.com/science/article/pii/S0167610502002325

  52. [52]

    Teutscher, F

    D. Teutscher, F. Bukreev, A. Kummerländer, S. Simonis, P. Bächler, A. Rezaee, M. Hermansdorfer, M. J. Krause, A digital urban twin enabling interactive pollution predictions and enhanced planning, Building and Environment 281 (2025) 113093.doi:10.1016/j.buildenv.2025.113093. URLhttps://www.sciencedirect.com/science/article/pii/S0360132325005748

  53. [53]

    Blonigan, R

    P. Blonigan, R. Chen, Q. Wang, J. Larsson, Towards adjoint sensitivity analysis of statistics in turbulent flow simulation, in: Proceedings of the Summer Program, Vol. 229, Center for Turbulence Research, Stanford Univ., 2012

  54. [54]

    Kummerländer, T

    A. Kummerländer, T. Bingert, S. Bock, F. Bukreev, D. Castroviejo, L. E. Czelusniak, D. Dapelo, C. Gaul, M. Dorn, L. Dorneles, J. Grafen, M. Grinschewski, S. Ito, J. Jeßberger, F. Kaiser, D. Khaza- eipoul, T.Krüger, A.Kumbhat, H.Kusumaatmaja, A.Nettekoven, A.Raeli, T.Riazantsev, M.Rennick, G. Prakash, F. Prinz, L. Sauterleute, M. Schecher, A. Schneider, Y....