Pressure Boundary Conditions Research Articles

Generalized and high-efficiency arbitrary-positioned buffer for smoothed particle hydrodynamics

This paper develops a generalized, high-efficiency buffer for particle generation and deletion at arbitrary-positioned in-/outlets in the smoothed particle hydrodynamics method. To achieve generality, we standardize the position comparison of particles with an arbitrary-positioned in-/outlet bound by introducing coordinate transformation. To enhance efficiency, particle candidates subjected to position comparison at a specific in-/outlet are restricted to those within the local cell-linked lists near the defined buffer region, thereby avoiding the inefficiency in the straightforward approach of sequentially checking all fluid particle positions across the computational domain. We validate the effectiveness and versatility of the developed buffer through two-dimensional and three-dimensional non-orthogonal and orthogonal, uni- and bidirectional flows with arbitrary-positioned in- and outlets, driven by pressure or velocity boundary conditions.

Data-driven macro-scale simulation for rapid electrolyte wetting in lithium-ion batteries

The electrolyte wetting process in lithium-ion battery manufacturing is a critical part of processes that affects battery performance and productivity. However, it is difficult to accurately measure and optimise this process with existing technologies. In this study, a three-dimensional macroscopic filling and wetting simulation model based on actual battery material parameters is constructed, which can simulate the wetting process of electrolyte in porous electrodes and separators. The model is employed to analyse effects of filling pressure pattern, boundary conditions and other process parameters on the wetting rate. The results demonstrate that the use of multilateral cyclic pressure filling can optimise the electrolyte wetting, which is in accordance with industry practice. Consequently, the study proceeds to investigate potential process optimisation strategies, including electrolyte selection and ambient temperature. These findings not only address limitations of traditional models, which employ simplified parameters, but also present a novel approach to enhance manufacturing efficiency and reduce cost of lithium batteries. This is of paramount importance for the sustainable development of lithium-ion battery industry.

Mathematical model and its solution for water-altering-gas (WAG) injection process incorporating the effect of miscibility, gravity, viscous fingering and permeability heterogeneity

AbstractThe oil recovery from the water-alternating-gas (WAG) injection process is significantly impacted by gravity, viscous fingering, and the permeability heterogeneity of the reservoir. Therefore, the combined effect of these parameters cannot be neglected in the WAG injection process. This article presents the development of a mathematical model of oil recovery and its solution for the WAG injection process that takes into account the combined effects of miscibility change, viscous fingering, gravity, and permeability heterogeneity in an inclined stratified reservoir. First, the governing equations and fractional flow functions were explained in relation to the effects of gravity, permeability heterogeneity, viscous fingering, and miscibility change in an inclined stratified porous medium. Then, a mathematical model was developed using fractional flow functions and conservation equations for both injected water and solvent. The model was generated in the form of a quasi-linear first-order partial differential equation, which was solved analytically in two dimensions (2-D) utilizing vector calculus. Next, this model was solved analytically by applying wave theory to practical constant pressure boundary conditions, which generate distinct waves at different times to provide pressure and saturation at the displacement front location. The total volumetric flux and breakthrough time are calculated from the analytical solution at various times. The presented analytical solutions can be used to predict different parameters for stratified porous media in a fast and efficient way. Finally, the results of analytical solution validated with high-resolution numerical simulation for a wide range of permeability heterogeneity, which shows excellent agreement for breakthrough time, saturation, and pressure versus displacement location of different waves at different times. This analytical solution will save time and money by offering guidance to engineers for analyzing the saturation and pressure distribution at different times and predicting oil recovery. It will also improve the understanding of the physics underlying the multiphase flow WAG injection process in heterogeneous reservoirs.

An improved pressure gradient method for viscous incompressible flows

The pressure gradient method solves the viscous incompressible flow with the pressure gradients, rather than the pressure, as unknown variables. Two variants of the pressure gradient method have been developed in the past but have not received much attention due to their unsatisfactory performance or implementation complexity. Based on the artificial compressibility concept, this study proposes an improved pressure gradient method. One distinct feature of this method is that it requires no pressure/pressure gradient boundary condition or special treatment on wall boundaries. An auxiliary variable is introduced to represent the velocity dilatation, greatly simplifying the spatial discretization and computational procedure. The mathematical formulations are elaborated and compared with the previous pressure gradient methods, followed by discussions of compatibility relationships, boundary condition setup, and an extension to a pressure Poisson-like equation. Four validation examples are performed for various flow scenarios, and the solutions and domain solenoidity are examined for each case. The study also compares associated computational methods, different pressure boundary conditions, and flow characteristics, demonstrating the benefits of the present method.

A numerical approach to overcome the very-low Reynolds number limitation of the artificial compressibility for incompressible flows

We propose a numerical approach to solve a long-standing challenge which is the applicability of the artificial compressibility (AC) formulation for solving the incompressible Navier—Stokes equations at very-low Reynolds numbers. A wide range of engineering applications involves very-low Reynolds number flows in Micro-ElectroMechanical Systems (MEMS) and in the fields of chemical-, agricultural- and biomedical engineering. It is known that the already existing numerical methods using the AC approach fail to provide physically correct results at very-low Reynolds numbers (Re ≤ 1). To overcome the limitation of the AC method for these engineering applications, we propose a higher-order Neumann-type pressure outflow boundary condition treatment along with their up to fourth-order numerical approximations. We found that the numerical treatment of the pressure at the outlet boundary plays the main role in overcoming the limitation of the AC method at very-low Reynolds numbers (Re << 1). Therefore, we provide numerical evidence on the accuracy of the AC method beyond its previously reported limitations, e.g., the low Reynolds number Oseen flow (Re << 1) is first presented in this work. A third-order explicit total-variation diminishing (TVD) Runge–Kutta scheme has been employed with standard finite difference spatial discretisation schemes for improving the accuracy of the numerical solution. For modelling strongly viscous flows, the Reynolds number ranges from 10−1 to 10−4. Overall, we found that the accuracy limitation of the AC method below Re < 1 can be overcome with an accurate numerical treatment of the outlet pressure boundary condition instead of using high-order schemes in the governing equations. For the investigated Reynolds number range (10−1 ≤ Re ≤ 10−4), the obtained results show that the relative errors were smaller than 1% for the numerical simulations performed on the configurations of both the two- and three-dimensional, straight microfluidic channels. The imposition of high-order derivative Neumann-type pressure outflow boundary conditions reduced the maximum relative errors of the numerical solutions from 85% and 95% to below than 1% at the outlet section of the two- and three-dimensional, straight microfluidic channel flows, respectively. Taking the advantage of the numerical approach proposed here, two- and three-dimensional benchmark problems employed in the current investigation in comparison with analytical solutions available in the literature, clearly demonstrate that the artificial compressibility can be used beyond its previously known constraints for very-low Reynolds number incompressible flows.

Multi-scale modeling of aerosol transport in a mouth-to-truncated bronchial tree system

Computational fluid particle dynamics (CFPD) is widely employed to predict aerosol transport in a truncated bronchial tree model on account of its capacity to reveal details of flow field and particle movement. However, setting a physiologically consistent boundary condition in the CFPD for the idealized or image-based truncated bronchial tree model is still a challenge. This paper proposes a multi-scale modeling method, which contains an Extend-Bronchial tree-Network (EBN) boundary condition for a mouth-to-truncated bronchi system. The comparison between EBN boundary condition and a commonly used uniform pressure (UP) boundary condition is conducted. Subsequently, EBN method is used to study the nano-micron (100 nm–10 μm) particles transport in the mouth-to-truncated bronchi model at different inhalation volume rates (15, 60, 90 L/min). Results show that EBN method is more physiologically rational and two methods differ in flow distribution in lobes, vortex structure, and particle transport. The maximum difference in flow rate distribution in lobes between two methods is about 20 %, while the maximum relative disparity of particle penetration fraction from lobes and deposition fraction in the TLB is about 93 % and 30 %, respectively. Meanwhile, this paper reveals the variation of deposition fraction and penetration fraction with the changes in particle diameter and inhalation volume. Deposition efficiency, deposition hotspots and deposition mechanism are also analyzed with inlet Stokes number (Stk) and Reynolds number (Re). This research establishes a foundation for the simulation of aerosol transport in a whole respiratory tract and provides references for inhalation drug delivery and air pollutant management.

Boundary vorticity of incompressible 2D flows

For a homogeneous incompressible 2D fluid confined within a bounded Lipschitz simply connected domain, homogeneous Neumann pressure boundary conditions are equivalent to a constant boundary vorticity. We investigate the rigidity of such conditions.

Degradation mechanism and assessment for different cathode based commercial pouch cells under different pressure boundary conditions

Lithium-ion pouch cell exhibits expansion behavior during cycling, which determines the overall performance and external pressure evolution. It is significant to reveal the impact of pressure boundary conditions on battery degradation. This study investigated the degradation mechanism of different cathode-based pouch cells (LiFePO4 (LFP) and Li(Ni0.6Co0.2Mn0.2)O2 (NCM622)) under four distinct pressure boundary conditions (I-II. clamping with two foam pads having varying compression force deflection (CFD) respectively, III. without foam pad, IV. unpressurized). One hundred of pre-experiment cycles determined the optimal external pressure (12.5 kPa) to slow down the degradation process. Subsequently, multi-cell paralleled cycling experiments were conducted for 1000 cycles. The capacity degradation of LFP and NCM cells with the optimal condition was 6.0 % and 12.6 % less than that of unpressurized cells. The electrochemical tests indicated that unpressurized cells had the fastest rate of lithium-ion loss, which is related to solid electrolyte interface (SEI) film growth and lithium plating. Post-mortem characterization analysis further revealed that the pressure boundary condition is crucial for the electrode morphology, pressure distribution, and gas generation, which affect battery degradation. The pressurized cells’ surface exhibited fewer instances of lithium plating. With the stiff foam clamped, pouch cell swelling can be absorbed while maintaining contact between cell components, resulting in fewer electrode folds and cracks. This study provides valuable insights for designing long-lifespan battery modules or packs.

Wetting and pressure gradient performance in a lattice Boltzmann color gradient model

An accurate implementation of wetting and pressure drop is crucial to correctly reproduce fluid displacement processes in porous media. Although several strategies have been proposed in the literature, a systematic comparison of them is needed to determine the most suitable for practical applications. Here, we carried out numerical simulations to investigate the performance of two widely used wettability schemes in the lattice Boltzmann color gradient model, namely, the geometrical wetting scheme by Leclaire et al. [Phys. Rev. E 95(3), 033306 (2017)](scheme-I) and the modified direction of the color gradient scheme by Akai et al. [Adv. Water Resour. 116, 56–66 (2018)] (scheme-II). We showed that scheme-II was more accurate in simulating static contact angles of a fluid droplet on a solid surface. However, scheme-I was more accurate in simulating a dynamic case of a binary fluid flow in a horizontal capillary tube described by the Washburn equation. Moreover, we investigated the performance of two popular pressure gradient implementation types. Type-I used the so-called Zou–He pressure boundary conditions at the inlet and the outlet of the domain, while type-II used an external body force as a pressure gradient. We showed that the type-I implementation was slightly more accurate in simulating a neutrally wetting fluid in a horizontal capillary tube described by the Washburn equation. We also investigated the differences between the two types of pressure gradient implementation in simulating two fluid displacement processes in a Bentheimer sandstone rock sample: the primary drainage and the imbibition displacement processes.

Pressure Transient Solutions for Unbounded and Bounded Reservoirs Produced and/or Injected via Vertical Well Systems with Constant Bottomhole Pressure

Various analytical solutions for computing production and injection-induced pressure changes in aquifers and oil reservoirs have been derived over the past century. All prior solutions assumed a constant well rate as the boundary condition. However, in many practical situations, the fluid withdrawal from and/or injection into such subsurface reservoirs occurs with the aid of pump devices that maintain a constant bottomhole pressure in the well. Until now, how the well rate will decline over time, based on the pressure difference in the well relative to the initial reservoir pressure, could not be rapidly computed analytically (using the diffusivity as the key governing system parameter), because no concise expression had been derived with the boundary condition of a constant bottomhole pressure. The present study shows how the pressure diffusion equation can be readily solved for wells acting as sinks and sources with a constant bottomhole pressure condition. We consider both fractured and unfractured completions, as well as injection and production modes. The new solutions do not require an elaborate time-stepped pressure-matching procedure as in nodal analysis, the only other physics-based analytical method currently available to compute the well rate decline when a constant bottomhole pressure production system is used, which unlike our new method proposed here is limited to single well systems.

Numerical assessment of using various outlet boundary conditions on the hemodynamics of an idealized left coronary artery model.

Vascular diseases are greatly influenced by the hemodynamic parameters and the accuracy of determining these parameters depends on the use of correct boundary conditions. The present work carries out a two-way fluid-structure interaction (FSI) simulation to investigate the effects of outlet pressure boundary conditions on the hemodynamics through the left coronary artery bifurcation with moderate stenosis (50%) in the left anterior descending (LAD) branch. The Carreau viscosity model is employed to characterise the shear-thinning behaviour of blood. The results of the study reveal that the employment of zero pressure at the outlet boundaries significantly overestimates the values of hemodynamic variables like wall shear stress (WSS), and time-averaged wall shear stress (TAWSS) compared with human healthy and pulsatile pressure outlet conditions. However, the difference between these variables is marginally low for human healthy and pulsatile pressure outlets. The oscillatory shear index (OSI) remains the same across all scenarios, indicating independence from the outlet boundary condition. Furthermore, the magnitude of negative axial velocity and pressure drop across the plaque are found to be higher at the zero pressure outlet boundary condition.

Extending gravitational potentials from the surface boundaries of compact objects

The solutions of the Einstein field equations of general relativity (GR) are prone to rendering systems which are physically non-viable as shown by Delgaty and Lake (1998). This does not detract from the success of general relativity but rather suggests the possibility for implementing new solution methods while being cautious that the resulting systems are indeed physically viable. This emphasizes the importance of applying appropriate criteria in closing the system of non-linear, coupled differential equations of GR. In the case of static systems describing massive compact bodies, an intrinsic property is the vanishing of the radial pressure at the surface boundary of the object which is embedded in an empty Schwarzschild exterior spacetime. In attempting to complete the gravitational description, we first assume a standard, physically plausible metric potential such as that of Finch and Skea. We then attempt to solve for the other metric component by imposing an ansatz which assists in extrapolating from the vanishing pressure boundary condition. Our model is guided by the physicality of the sound speed profiles and associated stability conditions.

Soil-tunnel interaction under the effect associated with the longitudinal direction

Longitudinal structural analysis of shield tunnels is studied by considering the tunnel as a Timoshenko beam based on elastic foundations under Vlasov's theory. This article presents the structural behavior of a Timoshenko-Vlasov beam jointly, using a single differential system that brings together all the equilibrium and deformation equations. Solving the presented formulation, shield tunnels can be covered under any type of action, ground pressure and support or boundary conditions. This new compacted notation facilitates the possibility of expressing the interaction between soil and structure by introducing the variability of longitudinal support conditions on the elastic springs. This differential system is resolved with the numeric procedure named Finite Transfer Method. To verify the effectiveness of the procedure followed, the structure of the subway tunnel in Shanghai has been modeled and the results obtained have been compared with those offered in the literature. The proposed model has been exemplified by introducing the variability of longitudinal elastic spring conditions representing actual soil behavior.

Detailed 3D URANS analysis of two-phase flow in an airlift pump

An airlift pump is a vertical tube that utilizes the buoyant effects of a gas to lift a liquid. Unlike a standard mechanical pump, the liquid flow rate through the airlift pump is not directly controlled; rather, it depends on the supplied gas flow rate, the tube length and diameter, and the relative height of the liquid supply free surface (submergence ratio). The present study uses the commercial CFD code ANSYS CFX to model the isothermal, 3D, transient flow in an airlift pump using water and air. The model applies pressure boundary conditions at both ends of the tube and specifies the mass flow rate of air through multiple openings in the side of the tube. The bottom of the tube is an inlet of water only and the outlet is a two-phase flow opening. A time-dependent, homogeneous, VOF two-phase RANS CFD modelling approach is used with the air treated as an ideal gas. This work found that a complete 3D domain was necessary for consistent prediction of the airlift performance and physically realistic two-phase flow structures. Statistical analysis of the two-phase flow structures was applied to characterize airlift pump instability and better understand the physics of the airlift pump.

Investigation of The Effect of Geometrical Parameters And Fluid Properties of Heat Sinks on Cooling By RSM Method

This study investigated the effect of the response surface method (RSM) on heat sinks designed in block types and using various fluids. The RSM method was applied to the data obtained from heat sinks designed in block type placed in both vertical and horizontal directions using water, mono, nanofluids, and hybrid nanofluids. The data were collected under five different pressure boundary conditions and applied to 144 data sets. The Box-Behnken method was used to analyze the design parameters and derive equations for seven different parameters: density, viscosity, specific heat, thermal conductivity, block thickness, block distances, and inlet pressure boundary conditions. The equations were used to determine the average CPU temperature, thermal resistance, and Performance Evaluation Criteria (PEC). The findings show that the R2 values for thermal resistance (Rth), average CPU temperature (Tm), and performance evaluation criteria (PEC) for flat arrangements are 99.21%, 99.21%, and 99.37%, respectively. The R2 values for the vertically designed geometries are 97.66%, 97.66%, and 98.45%, indicating a strong correlation between the results obtained from FLUENT and the ANOVA statistical results. The linear, square, and cubic effects of each variable had a significant impact on each solution. The study concluded that the RSM method has a significant effect on heat sinks with higher R2 values in horizontal arrangements and a higher distance between blocks. Another important result showed that increasing the block thickness also has a significant effect on Rth and Tm, homogenizing the temperature distribution while increasing the cooling capacity.

Computing pulsatile blood flow of coronary artery under incomplete boundary conditions

BackgroundAccurate measurement of pulsatile blood flow in the coronary arteries enables coronary wave intensity analysis, which can serve as an indicator for assessing coronary artery physiology and myocardial viability. Computational fluid dynamics (CFD) methods integrating coronary angiography images and fractional flow reserve (FFR) offer a novel approach for computing mean coronary blood flow. However, previous methods neglect the inertial effect of blood flow, which may have great impact on pulsatile blood flow calculation. To improve the accuracy of pulsatile blood flow calculation, a novel CFD based method considering the inertia term is proposed. MethodsA flow resistance model based on Pressure-Flow vs.Time curves is proposed to model the resistance of the epicardial artery. The parameters of the flow resistance model can be fitted from the simulated pulsating flow rates and pressure drops of a specific mode. Then, pulsating blood flow can be calculated by combining the incomplete pressure boundary conditions under pulsating conditions which are easily obtained in clinic. Through simulation experiments, the effectiveness of the proposed method is validated in idealized and reconstructed 3D model of coronary artery. The impacts of key parameters for generating the simulated pulsating flow rates and pressure drops on the accuracy of pulsatile blood flow calculation are also investigated. ResultsFor the idealized model, the previously proposed Pressure-Flow model has a significant leading effect on the computed blood flow waveform in the moderate model, and this leading effect disappears with the increase of the degree of stenosis. The improved model proposed in this paper has no leading effect, the root mean square error (RMSE) of the proposed model is low (the left coronary mode:≤0.0160, the right coronary mode:≤0.0065) for all simulated models, and the RMSE decreases with an increase of stenosis. The RMSE is consistently small (≤0.0217) as the key parameters of the proposed method vary in a large range. It is verified in the reconstructed model that the proposed model significantly reduces the RMSE of patients with moderate stenosis (the Pressure-Flow model:≤0.0683, the Pressure-Flow vs.Time model:≤0.0297), and the obtained blood flow waveform has a higher coincidence with the simulated reference waveform. ConclusionsThis paper confirms that ignoring the effect of inertia term can significantly affect the accuracy of calculating pulsatile blood flow in moderate stenosis lesions, and the new method proposed in this paper can significantly improves the accuracy of calculating pulsatile blood flow in moderate stenosis lesions. The proposed method provides a convenient clinical method for obtaining pressure-synchronized blood flow, which is expected to facilitate the application of waveform analysis in the diagnosis of coronary artery disease.

A MAC grid based FFT-AMIB solver for incompressible Stokes flows with interfaces and singular forces

In this paper, a second order accurate Augmented Matched Interface and Boundary (AMIB) method is introduced for solving the incompressible Stokes flows with interfaces and singular forces. Based on the MAC staggered grid for velocity and pressure, the zeroth order and first order jump conditions are repeatedly enforced in the AMIB scheme to generate fictitious values around the interface, which allow an accurate approximation of the Cartesian derivative jumps. By treating all jump quantities as auxiliary variables and coupling them with the corrected finite difference formulas, the Stokes equations can be discretized into an augmented system. The proposed FFT-AMIB solver does not need to take the pressure boundary condition into account. Moreover, in the Schur complement solution of the augmented system, the discrete Laplacian can be efficiently inverted by using the fast Fourier transform (FFT). Numerical results show that the FFT-AMIB solver is very efficient and can achieve second order accuracy for both velocity and pressure. The iteration number of Bi-CGSTAB in solving the resulting augmented system only weakly depends on the mesh size. When the interface is allowed to be moved under the surface tension, the proposed algorithm can maintain the divergence-free condition and area conservation very well.

Uncertainty quantification of the lattice Boltzmann method focussing on studies of human-scale vascular blood flow

Uncertainty quantification is becoming a key tool to ensure that numerical models can be sufficiently trusted to be used in domains such as medical device design. Demonstration of how input parameters impact the quantities of interest generated by any numerical model is essential to understanding the limits of its reliability. With the lattice Boltzmann method now a widely used approach for computational fluid dynamics, building greater understanding of its numerical uncertainty characteristics will support its further use in science and industry. In this study we apply an in-depth uncertainty quantification study of the lattice Boltzmann method in a canonical bifurcating geometry that is representative of the vascular junctions present in arterial and venous domains. These campaigns examine how quantities of interest—pressure and velocity along the central axes of the bifurcation—are influenced by the algorithmic parameters of the lattice Boltzmann method and the parameters controlling the values imposed at inlet velocity and outlet pressure boundary conditions. We also conduct a similar campaign on a set of personalised vessels to further illustrate the application of these techniques. Our work provides insights into how input parameters and boundary conditions impact the velocity and pressure distributions calculated in a simulation and can guide the choices of such values when applied to vascular studies of patient specific geometries. We observe that, from an algorithmic perspective, the number of time steps and the size of the grid spacing are the most influential parameters. When considering the influence of boundary conditions, we note that the magnitude of the inlet velocity and the mean pressure applied within sinusoidal pressure outlets have the greatest impact on output quantities of interest. We also observe that, when comparing the magnitude of variation imposed in the input parameters with that observed in the output quantities, this variability is particularly magnified when the input velocity is altered. This study also demonstrates how open-source toolkits for validation, verification and uncertainty quantification can be applied to numerical models deployed on high-performance computers without the need for modifying the simulation code itself. Such an ability is key to the more widespread adoption of the analysis of uncertainty in numerical models by significantly reducing the complexity of their execution and analysis.

Pressure boundary conditions for immersed-boundary methods

Immersed boundary methods have seen an enormous increase in popularity over the past two decades, especially for problems involving complex moving/deforming boundaries. In most cases, the boundary conditions on the immersed body are enforced via forcing functions in the momentum equations, which in the case of fractional step methods may be problematic due to: i) creation of slip-errors resulting from the lack of explicitly enforcing boundary conditions on the (pseudo-)pressure on the immersed body; ii) coupling of the solution in the fluid and solid domains via the Poisson equation. Examples of fractional-step formulations that simultaneously enforce velocity and pressure boundary conditions have also been developed, but in most cases the standard Poisson equation is replaced by a more complex system which requires expensive iterative solvers. In this work we propose a new formulation to enforce appropriate boundary conditions on the pseudo-pressure as part of a fractional-step approach. The overall treatment is inspired by the ghost-fluid method typically utilized in two-phase flows. The main advantage of the algorithm is that a standard Poisson equation is solved, with all the modifications needed to enforce the boundary conditions being incorporated within the right-hand side. As a result, fast solvers based on trigonometric transformations can be utilized. We demonstrate the accuracy and robustness of the formulation for a series of problems with increasing complexity.

Induction of Controllable Vortex Flow in a New Aorta Stenosis Model for Potential Aorta Mechanobiology Study: A Flow Simulation Platform

Background: Abdominal aortic aneurysms (AAA) are common, particularly among individuals over age 65, with a prevalence of 9%. To better understand the natural history of AAAs, one critical knowledge gap must be filled to elucidate the role of vortical flow in vascular degradation and thrombosis formation. We aimed to induce various types of vortical flow with aneurysm-like hemodynamic environments using a novel aorta stenosis model. Such a model will enable us to investigate the interplays between disturbed hemodynamics and vascular pathological remodeling. Methods: In this study, the hemodynamics and geometry of the aorta in rabbits were used to simulate the physiological flow conditions after two adjacent stenoses were created virtually with varying degrees of area reduction (30-70%) and spacing (5-6.8 mm). A physiological blood flow (rate) waveform measured in rabbits using ultrasound Doppler (normalized to 3.0 mL/s) was prescribed to the inlet (i.e., descending aorta), and zero pressure boundary conditions were applied at two outlets (i.e., iliac arteries). 3D computational fluid dynamics (CFD) simulation in five different stenosis configurations was performed using commercial software (Fluent, Version 20, Ansys Inc., PA). In-house software assessed the evolution of flow vortices over three distinct regions post stenosis using an established method. The total volume of vortex flow, the number of vortices, and the phase-to-phase overlap of vortex flows within different post-stenosis regions were derived to characterize the vortex flow. Results: Quantitative and qualitative flow assessments were performed for all five CFD models. Firstly, in all models, we found consistent patterns of the three vortex flow parameters, indicating that the adjacent stenoses induced three different hemodynamic zones in the post-stenosis regions, namely, stable vortical flow (after first stenosis), transient flow (after second stenosis), unstable vortical flow (further distal to second stenosis). Moreover, increased stenosis degree or reduced spacing led to reduced vortex flow number but increased total volume of vortex flow. The distinctions of the three regions were most significant in the model with 50% and then 30% stenoses, and with a 5 mm (center-to-center) spacing between two stenoses. Conclusions: CFD simulations can offer a powerful tool to predict complex flows using subject-specific vasculature. Such a flow simulation platform is valuable for guiding experimental design or therapy in various diseases. We demonstrated that it is feasible to adjust and achieve multiple types of vortical flows with the novel stenosis model. The three zones with distinct hemodynamic environments allow us to investigate the vascular remodeling regulated by the specifics of the eddies. Our ongoing work is implementing optimized aorta stenosis models to preclinical or in vitro studies to reveal the interplays between varying disturbed flow and aneurysm remodeling. We acknowledge funding support from NIH/NIBIB (R01-EB029570A1) and the Health Research Institute of Michigan Technological University. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.