2022
|
Waldmann, Moritz; Rüttgers, Mario; Lintermann, Andreas; Schröder, Wolfgang Virtual Surgeries of Nasal Cavities Using a Coupled Lattice-Boltzmann–Level-Set Approach Journal Article In: Journal of Engineering and Science in Medical Diagnostics and Therapy, vol. 5, iss. 3, 2022, ISSN: 2572-7958. @article{Waldmann2022,
title = {Virtual Surgeries of Nasal Cavities Using a Coupled Lattice-Boltzmann–Level-Set Approach},
author = {Waldmann, Moritz and Rüttgers, Mario and Lintermann, Andreas and Schröder, Wolfgang},
url = {https://asmedigitalcollection.asme.org/medicaldiagnostics/article/doi/10.1115/1.4054042/1139371/Virtual-Surgeries-of-Nasal-Cavities-Using-a},
doi = {10.1115/1.4054042},
issn = {2572-7958},
year = {2022},
date = {2022-03-31},
urldate = {2022-03-31},
journal = {Journal of Engineering and Science in Medical Diagnostics and Therapy},
volume = {5},
issue = {3},
abstract = {Fluid mechanical properties of respiratory flow such as pressure loss, temperature distribution, or wall-shear stress characterize the physics of a nasal cavity. Simulations based on computational fluid dynamics (CFD) methods are able to deliver in-depth details on respiration. Integrating such tools into virtual surgery environments may support physicians in their decision-making process. In this study, a lattice-Boltzmann (LB) flow solver is coupled to a level-set (LS) method to modify the shape of a nasal cavity at simulation run time in a virtual surgery. The geometry of a presurgical nasal cavity obtained from computer tomography (CT) datasets is smoothly adapted toward a postsurgical geometry given by the surgeon using an interpolation approach based on a LS method. The influence of the modification on the respiratory flow is analyzed in silico. The methods are evaluated by simulating a virtual surgery of a stenotic pipe and juxtaposing the results to cases using static geometries and by comparing them to literature findings. The results for both the stenotic pipe and the nasal cavity are in perfect agreement with the expected outcomes. For the nasal cavity, a shape is found that reduces the nasal resistance by 25.3% for inspiration at a volumetric flow rate of V˙=250 ml/s. The heating capability is retained despite the geometry modification. The simulation results support the surgeon in evaluating a planned surgery and in finding an improved surgery for the patient.},
keywords = {CFD Applications, Geometry, Lattice-Boltzmann method, Medizin, nasal cavity, Pipes, Pressure, Respiratory Flow Computation, Strömungssimulation, surgical indication},
pubstate = {published},
tppubtype = {article}
}
Fluid mechanical properties of respiratory flow such as pressure loss, temperature distribution, or wall-shear stress characterize the physics of a nasal cavity. Simulations based on computational fluid dynamics (CFD) methods are able to deliver in-depth details on respiration. Integrating such tools into virtual surgery environments may support physicians in their decision-making process. In this study, a lattice-Boltzmann (LB) flow solver is coupled to a level-set (LS) method to modify the shape of a nasal cavity at simulation run time in a virtual surgery. The geometry of a presurgical nasal cavity obtained from computer tomography (CT) datasets is smoothly adapted toward a postsurgical geometry given by the surgeon using an interpolation approach based on a LS method. The influence of the modification on the respiratory flow is analyzed in silico. The methods are evaluated by simulating a virtual surgery of a stenotic pipe and juxtaposing the results to cases using static geometries and by comparing them to literature findings. The results for both the stenotic pipe and the nasal cavity are in perfect agreement with the expected outcomes. For the nasal cavity, a shape is found that reduces the nasal resistance by 25.3% for inspiration at a volumetric flow rate of V˙=250 ml/s. The heating capability is retained despite the geometry modification. The simulation results support the surgeon in evaluating a planned surgery and in finding an improved surgery for the patient. | |
2020
|
Grosch, Alice; Waldmann, Moritz; Göbbert, Jens Henrik; Lintermann, Andreas A Web-Based Service Portal to Steer Numerical Simulations on High-Performance Computers Proceedings Article In: Samo Mahnič-Kalamiza Tomaž Jarm, Aleksandra Cvetkoska (Ed.): 8th European Medical and Biological Engineering Conference (=
EMBEC 2020), IFMBE Proceedings, pp. 57-65, Ljubljana, 2020. @inproceedings{Grosch2021,
title = {A Web-Based Service Portal to Steer Numerical Simulations on High-Performance Computers},
author = {Grosch, Alice and Waldmann, Moritz and Göbbert, Jens Henrik and Lintermann, Andreas},
editor = {Tomaž Jarm, Samo Mahnič-Kalamiza, Aleksandra Cvetkoska, Damijan Miklavčič},
url = {https://link.springer.com/chapter/10.1007%2F978-3-030-64610-3_8},
doi = {10.1007/978-3-030-64610-3_8},
year = {2020},
date = {2020-11-30},
booktitle = {8th European Medical and Biological Engineering Conference (=
EMBEC 2020), IFMBE Proceedings},
pages = {57-65},
address = {Ljubljana},
abstract = {Benefiting and accessing high-performance computing resources can be quite difficult. Unlike domain scientists with a background in computational science, non-experts coming from, e.g., various medical fields, have almost no chance to run numerical simulations on large-scale systems. To provide easy access and a user-friendly interface to supercomputers, a web-based service portal, which under the hood takes care of authentication, authorization, job submission, and interaction with a simulation framework is presented. The service is exemplary developed around a simulation framework capable of efficiently running computational fluid dynamics simulations on high-performance computers. The framework uses a lattice-Boltzmann method to simulate and analyze respiratory flows. The implementation of such a web-portal allows to steer the simulation and represents a new diagnostic tool in the field of ear, nose, and throat treatment.},
keywords = {Computational Fluid Dynamics, High-performance computing, Lattice-Boltzmann method, Respiratory flows, Service portal},
pubstate = {published},
tppubtype = {inproceedings}
}
Benefiting and accessing high-performance computing resources can be quite difficult. Unlike domain scientists with a background in computational science, non-experts coming from, e.g., various medical fields, have almost no chance to run numerical simulations on large-scale systems. To provide easy access and a user-friendly interface to supercomputers, a web-based service portal, which under the hood takes care of authentication, authorization, job submission, and interaction with a simulation framework is presented. The service is exemplary developed around a simulation framework capable of efficiently running computational fluid dynamics simulations on high-performance computers. The framework uses a lattice-Boltzmann method to simulate and analyze respiratory flows. The implementation of such a web-portal allows to steer the simulation and represents a new diagnostic tool in the field of ear, nose, and throat treatment. | |
Lintermann, Andreas; Schröder, Wolfgang Lattice–Boltzmann simulations for complex geometries on high-performance computers Journal Article In: CEAS Aeronautical Journal, 2020, ISBN: 1869-5582. @article{Lintermann2020c,
title = {Lattice–Boltzmann simulations for complex geometries on high-performance computers},
author = {Lintermann, Andreas and Schröder, Wolfgang },
url = {http://link.springer.com/10.1007/s13272-020-00450-1},
doi = {10.1007/s13272-020-00450-1},
isbn = {1869-5582},
year = {2020},
date = {2020-05-13},
journal = {CEAS Aeronautical Journal},
abstract = {Complex geometries pose multiple challenges to the field of computational fluid dynamics. Grid generation for intricate objects is often difficult and requires accurate and scalable geometrical methods to generate meshes for large-scale computations. Such simulations, furthermore, presume optimized scalability on high-performance computers to solve high-dimensional physical problems in an adequate time. Accurate boundary treatment for complex shapes is another issue and influences parallel load-balance. In addition, large serial geometries prevent efficient computations due to their increased memory footprint, which leads to reduced memory availability for computations. In this paper, a framework is presented that is able to address the aforementioned problems. Hierarchical Cartesian boundary-refined meshes for complex geometries are obtained by a massively parallel grid generator. In this process, the geometry is parallelized for efficient computation. Simulations on large-scale meshes are performed by a high-scaling lattice–Boltzmann method using the second-order accurate interpolated bounce-back boundary conditions for no-slip walls. The method employs Hilbert decompositioning for parallel distribution and is hybrid MPI/OpenMP parallelized. The parallel geometry allows to speed up the pre-processing of the solver and massively reduces the local memory footprint. The efficiency of the computational framework, the application of which to, e.g., subsonic aerodynamic problems is straightforward, is shown by simulating clearly different flow problems such as the flow in the human airways, in gas diffusion layers of fuel cells, and around an airplane landing gear configuration},
keywords = {Airway, Computational Fluid Dynamics, High performance computing, Large-Scale Simulation Data, Lattice-Boltzmann method},
pubstate = {published},
tppubtype = {article}
}
Complex geometries pose multiple challenges to the field of computational fluid dynamics. Grid generation for intricate objects is often difficult and requires accurate and scalable geometrical methods to generate meshes for large-scale computations. Such simulations, furthermore, presume optimized scalability on high-performance computers to solve high-dimensional physical problems in an adequate time. Accurate boundary treatment for complex shapes is another issue and influences parallel load-balance. In addition, large serial geometries prevent efficient computations due to their increased memory footprint, which leads to reduced memory availability for computations. In this paper, a framework is presented that is able to address the aforementioned problems. Hierarchical Cartesian boundary-refined meshes for complex geometries are obtained by a massively parallel grid generator. In this process, the geometry is parallelized for efficient computation. Simulations on large-scale meshes are performed by a high-scaling lattice–Boltzmann method using the second-order accurate interpolated bounce-back boundary conditions for no-slip walls. The method employs Hilbert decompositioning for parallel distribution and is hybrid MPI/OpenMP parallelized. The parallel geometry allows to speed up the pre-processing of the solver and massively reduces the local memory footprint. The efficiency of the computational framework, the application of which to, e.g., subsonic aerodynamic problems is straightforward, is shown by simulating clearly different flow problems such as the flow in the human airways, in gas diffusion layers of fuel cells, and around an airplane landing gear configuration | |
Waldmann, Moritz; Lintermann, Andreas; Choi, Yoon Jeong; Schröder, Wolfgang Analysis of the Effects of MARME Treatment on Respiratory Flow Using the Lattice-Boltzmann Method Proceedings Article In: New Results in Numerical and Experimental Fluid Mechanics , pp. 853-863, Springer International Publishing, Darmstadt, Germany, 2020. @inproceedings{Waldmann2020,
title = {Analysis of the Effects of MARME Treatment on Respiratory Flow Using the Lattice-Boltzmann Method},
author = {Waldmann, Moritz and Lintermann, Andreas and Choi, Yoon Jeong and Schröder, Wolfgang },
url = {http://link.springer.com/10.1007/978-3-030-25253-3},
doi = {10.1007/978-3-030-25253-3_80},
year = {2020},
date = {2020-01-02},
booktitle = {New Results in Numerical and Experimental Fluid Mechanics },
volume = {XII},
pages = {853-863},
publisher = {Springer International Publishing},
address = {Darmstadt, Germany},
abstract = {Transverse maxillary deficiency is a common pathological condition. Patients suffering from this pathology often have narrowed airways compared to healthy humans. To cure such an anatomic defective position, a new method, the Miniscrew-Assisted Rapid Maxillary Expansion (MARME), has been developed. In previous studies, the effects of this treatment on respiration have been analyzed by examining the volume of a nasal cavity and the corresponding nasopharynx before and after treatment. In this study the fluid mechanical effects of MARME treatment on the respiratory flow and on the breathing capability are analyzed numerically. The realistic three-dimensional geometries of the nasal cavity employed for the simulation are reconstructed from Computer Tomography images. The flow within these geometries is simulated using a thermal Lattice-Boltzmann method. The results confirm that the respiratory resistance and the average wall-shear stress decrease after the MARME treatment. The heating capability, however, deteriorates.},
keywords = {Lattice-Boltzmann method, MARME, Nasal cavity flows},
pubstate = {published},
tppubtype = {inproceedings}
}
Transverse maxillary deficiency is a common pathological condition. Patients suffering from this pathology often have narrowed airways compared to healthy humans. To cure such an anatomic defective position, a new method, the Miniscrew-Assisted Rapid Maxillary Expansion (MARME), has been developed. In previous studies, the effects of this treatment on respiration have been analyzed by examining the volume of a nasal cavity and the corresponding nasopharynx before and after treatment. In this study the fluid mechanical effects of MARME treatment on the respiratory flow and on the breathing capability are analyzed numerically. The realistic three-dimensional geometries of the nasal cavity employed for the simulation are reconstructed from Computer Tomography images. The flow within these geometries is simulated using a thermal Lattice-Boltzmann method. The results confirm that the respiratory resistance and the average wall-shear stress decrease after the MARME treatment. The heating capability, however, deteriorates. | |
2017
|
Lintermann, Andreas; Schröder, Wolfgang A Hierarchical Numerical Journey through the Nasal Cavity: From Nose-Like Models to Real Anatomies Journal Article In: Flow, Turbulence and Combustion, 2017, ISSN: 1386-6184. @article{Lintermann2017FTaC,
title = {A Hierarchical Numerical Journey through the Nasal Cavity: From Nose-Like Models to Real Anatomies},
author = {Lintermann, Andreas and Schröder, Wolfgang},
editor = {Springer Netherlands},
url = {http://rhinodiagnost.eu/wp-content/uploads/2017/12/paper_FTAC_SI_health_Lintermann.pdf, A Hierarchical Numerical Journey through the Nasal Cavity: From Nose-Like Models to Real Anatomies},
doi = {10.1007/s10494-017-9876-0},
issn = {1386-6184},
year = {2017},
date = {2017-12-20},
issuetitle = {special issue "CFD in Health"},
journal = {Flow, Turbulence and Combustion},
abstract = {The immense increase of computational power in the past decades led to an evolution of numerical simulations in all kind of engineering applications. New developments in medical technologies in rhinology employ computational fluid dynamics methods to explore pathologies from a fluid-mechanics point of view. Such methods have grown mature and are about to enter daily clinical use to support doctors in decision making. In light of the importance of effective respiration on patient comfort and health care costs, individualized simulations ultimately have the potential to revolutionize medical diagnosis, drug delivery, and surgery planning. The present article reviews experiments, simulations, and algorithmic approaches developed at RWTH Aachen University that have evolved from fundamental physical analyses using nose-like models to patient-individual analyses based on realistic anatomies and high resolution computations in hierarchical manner.},
keywords = {Digital particle image velocimetry, Finite volume method, High performance computing, Lattice-Boltzmann method, Nasal cavity flows},
pubstate = {published},
tppubtype = {article}
}
The immense increase of computational power in the past decades led to an evolution of numerical simulations in all kind of engineering applications. New developments in medical technologies in rhinology employ computational fluid dynamics methods to explore pathologies from a fluid-mechanics point of view. Such methods have grown mature and are about to enter daily clinical use to support doctors in decision making. In light of the importance of effective respiration on patient comfort and health care costs, individualized simulations ultimately have the potential to revolutionize medical diagnosis, drug delivery, and surgery planning. The present article reviews experiments, simulations, and algorithmic approaches developed at RWTH Aachen University that have evolved from fundamental physical analyses using nose-like models to patient-individual analyses based on realistic anatomies and high resolution computations in hierarchical manner. | |