Mean Shear Stress Research Articles

A simulation-based mechanistic study of turbulent wind blowing over opposing water waves

Abstract

The behaviour of Bolders Bank glacial till under undrained cyclic loading

Analysis of foundation behaviour under repeated loading can be important to the design of offshore facilities, towers, bridges, wind turbines and other structures. Although detailed guidance is available on how some geomaterials behave under cycling, few such studies have been reported on the glacial formations that are widespread across parts of northern Europe and under the North and Baltic Seas. This paper presents a cyclic laboratory investigation involving block samples of Bolders Bank till, which is one of the most extensive North Sea glacial formations. Static and cyclic triaxial tests are reported on nominally identical, low-plasticity, high-overconsolidation-ratio specimens from Cowden, near Hull in the UK. Twenty-three cyclic tests are reported on specimens that were re-consolidated to K0 stresses before experiencing up to 3500 undrained cycles involving a range of mean and cyclic shear stress combinations. The impacts of cycling on effective stress paths and strain development, cyclic stiffness and damping ratios are reported and interpreted with respect to parallel index, oedometer and monotonic triaxial compression and extension tests. Stable, metastable and unstable patterns of behaviour are identified, along with different cyclic failure modes. The styles of cyclic response are related to the till's static yielding behaviour. While the till can only manifest quasi-elastic behaviour within a very small (Y1) kinematic yield surface (KYS), a larger second (Y2) KYS is identified within which repeated loading leads to a non-linear yet stable response, with negligible mean effective stress drifts or stiffness degradation with low and stabilising strain accumulation rates. Cyclic paths that engage and relocate the Y2 surface lead to greater permanent strains, mean effective stress drifts and stiffness decays that become progressively more marked as the magnitudes of the cyclic stress perturbation and the number of cycles increase. While cycling under stable or metastable conditions increased the ultimate undrained strength of specimens that did not develop excessive strains, most cyclic paths that exceeded and climbed the till's Hvorslev surface were unstable and eventually failed. The experiments identified the key factors that affect the till's response to repeated loading and provide a basis for developing, testing and calibrating cyclic constitutive models and establishing simplified design procedures for comparable tills.

Tendon and Cytokine Marker Expression by Human Bone Marrow Mesenchymal Stem Cells in a Hyaluronate/Poly-Lactic-Co-Glycolic Acid (PLGA)/Fibrin Three-Dimensional (3D) Scaffold.

We developed a (three-dimensional) 3D scaffold, we named HY-FIB, incorporating a force-transmission band of braided hyaluronate embedded in a cell localizing fibrin hydrogel and poly-lactic-co-glycolic acid (PLGA) nanocarriers as transient components for growth factor controlled delivery. The tenogenic supporting capacity of HY-FIB on human-Bone Marrow Mesenchymal Stem Cells (hBM-MSCs) was explored under static conditions and under bioreactor-induced cyclic strain conditions. HY-FIB elasticity enabled to deliver a mean shear stress of 0.09 Pa for 4 h/day. Tendon and cytokine marker expression by hBM-MSCs were studied. Results: hBM-MSCs embedded in HY-FIB and subjected to mechanical stimulation, resulted in a typical tenogenic phenotype, as indicated by type 1 Collagen fiber immunofluorescence. RT-qPCR showed an increase of type 1 Collagen, scleraxis, and decorin gene expression (3-fold, 1600-fold, and 3-fold, respectively, at day 11) in dynamic conditions. Cells also showed pro-inflammatory (IL-6, TNF, IL-12A, IL-1β) and anti-inflammatory (IL-10, TGF-β1) cytokine gene expressions, with a significant increase of anti-inflammatory cytokines in dynamic conditions (IL-10 and TGF-β1 300-fold and 4-fold, respectively, at day 11). Mechanical signaling, conveyed by HY-FIB to hBM-MSCs, promoted tenogenic gene markers expression and a pro-repair cytokine balance. The results provide strong evidence in support of the HY-FIB system and its interaction with cells and its potential for use as a predictive in vitro model.

Is one dental mini-implant biomechanically appropriate for the retention of a mandibular overdenture? A comparison with Morse taper and external hexagon platforms

Statement of problemLimited information is available to clinicians on the use of dental mini-implants (MI) as opposed to standard-diameter implants (SDIs) for the stabilization of implant-retained mandibular overdentures (MOs). PurposeThe purpose of this in vitro and finite element analysis study was to analyze and compare the biomechanical behavior of MOs with either 1 or 2 implants with external hexagon (EH), Morse taper (MT) SDIs, and MIs. Material and methodsThirty photoelastic models (n=30) of each group (n=5) of SDIs (EH-1, EH-2, MT-1, MT-2) and MI (MI-1, MI-2) were fabricated for posterior, peri-implant, and total maximum shear stress evaluation by quantitative photoelastic analysis. One specimen of each group was further used to create the 6 computational models to be analyzed by finite element analysis. The maximum von Mises values and stress maps were plotted for each ductile component. Two types of load were applied to the overdenture: a150-N load bilaterally and simultaneously on the first molar and a 100-N load on the incisal edge of the central incisors at a 30-degree angle. The data were subjected to the 2-way ANOVA test and the Tukey honestly significant difference test (α=.05). ResultsThe EH-2 and MT-2 showed the lowest posterior (P<.001) and total (P<.05) mean shear stress values. For peri-implant shear stress, no difference was found among all groups (P>.05). Regardless of the loading area, the MI-1 and MI-2 groups showed the lowest von Mises stress values. However, for implant housing, the MI-1 group, under incisor loading, presented greater stress, followed by MT-1, EH-1, EH-2, MI-2, and MT-2. The attachment was the most overloaded structure, with high values under incisor loading, especially for the groups with 2 implants (MT-2, EH-2) as compared with the other models. ConclusionsBiomechanically, regardless of the implant number, MI is a promising rehabilitation method with similar peri-implant shear stress and lower von Mises stress on the implant when compared with SDIs for MOs.

Modeling Bed Shear Stress Distribution in Rectangular Channels Using the Entropic Parameter.

The evaluation of bed shear stress distribution is fundamental to predicting the transport of sediments and pollutants in rivers and to designing successful stable open channels. Such distribution cannot be determined easily as it depends on the velocity field, the shape of the cross section, and the bed roughness conditions. In recent years, information theory has been proven to be reliable for estimating shear stress along the wetted perimeter of open channels. The entropy models require the knowledge of the shear stress maximum and mean values to calculate the Lagrange multipliers, which are necessary to the resolution of the shear stress probability distribution function. This paper proposes a new formulation which stems from the maximization of the Tsallis entropy and simplifies the calculation of the Lagrange coefficients in order to estimate the bed shear stress distribution in open-channel flows. This formulation introduces a relationship between the dimensionless mean shear stress and the entropic parameter which is based on the ratio between the observed mean and maximum velocity of an open-channel cross section. The validity of the derived expression was tested on a large set of literature laboratory measurements in rectangular cross sections having different bed and sidewall roughness conditions as well as various water discharges and flow depths. A detailed error analysis showed good agreement with the experimental data, which allowed linking the small-scale dynamic processes to the large-scale kinematic ones.

Finite element analysis on rolling contact fatigue of surface nanostructured steel (Effect of friction coefficient on mean shear stress under cyclic loading)

Finite element analysis on rolling contact fatigue of surface nanostructured steel (Effect of friction coefficient on mean shear stress under cyclic loading)

Altered hemodynamics during arteriovenous fistula remodeling leads to reduced fistula patency in female mice

ObjectiveThe arteriovenous fistula (AVF) is the preferred method of dialysis access because of its proven superior long-term outcomes. However, women have lower rates of AVF patency and utilization than men. We used a novel mouse AVF model that recapitulates human AVF maturation to determine whether there are differences in AVF patency in female and male mice. MethodsAortocaval fistulas were created in female and male C57BL/6 mice (9-10 weeks). At days 0, 3, 7, and 21, infrarenal inferior vena cava (IVC) and aortic diameters and flow velocity were monitored by Doppler ultrasound and used to calculate the vessel diameter, blood flow, and shear stress. AVF were harvested, and expression of proteins was examined by proteomic analysis and immunofluorescence and of messenger RNA by quantitative polymerase chain reaction analysis. ResultsAt baseline, female mice weighed less and had lower IVC velocity and smaller magnitudes of shear stress, but there was no significant difference in IVC diameter and thickness. After AVF creation, both female and male mice had similar IVC dilation and thickening with no significant differences in IVC wall thickness at day 21. However, female mice had diminished AVF patency by day 42 (25.7% vs 64.3%; P = .039). During fistula remodeling, female mice had lower IVC mean velocity and shear stress magnitude and increased spectral broadening (days 0-21). Messenger RNA and protein expression of Krüppel-like factor 2, endothelial nitric oxide synthase, and vascular cell adhesion molecule 1 was similar at baseline in female and male mice but increased in the AVF only in male mice but not in female mice (day 21). Proteomic analysis of female and male mice detected 56 proteins expressed at significantly higher levels in the IVC of female mice and 67 proteins expressed at significantly higher levels in the IVC of male mice (day 7); function-specific analysis showed that the IVC of male mice overexpressed proteins that belong to pathways implicated in the regulation of vascular function, thrombosis, response to flow, and vascular remodeling. ConclusionsAVF in female mice have diminished patency, preceded by lower velocity, reduced magnitudes of shear stress, and less laminar flow during remodeling. There is also sex-specific differential expression of proteins involved in thrombosis, response to laminar flow, inflammation, and proliferation. These findings suggest that hemodynamic changes during fistula maturation may play an important role underlying the diminished rates of AVF utilization in women.

Experimental Observation on the Pure Torsional Ratchetting of Polycarbonate Polymer at Room Temperature

The stress‐controlled pure torsional cyclic tests are carried out to investigate the torsional ratchetting of polycarbonate (PC) polymer at room temperature. The effects of applied shear mean stress, stress amplitude, stress rate, peak stress hold, and stress history on the torsional ratchetting are discussed. The shear strain of tubular specimen is measured by a noncontact digital image correlation (DIC) apparatus. The results show that the torsional ratchetting of the polymer obviously depends on the applied shear stress level, stress rate, and peak stress hold; the shear ratchetting strain and its rate increase with the increasing mean stress, stress amplitude, and peak stress hold time and with the decreasing stress rate. Moreover, the torsional ratchetting depends on the stress history. A higher stress level cyclic loading history restrains the evolution of torsional ratchetting in the subsequent lower stress level cyclic loading, while the lower stress level cyclic loading history promotes the torsional ratchetting of the subsequent higher level cyclic loading.

Effect of transverse ridge microtopography on the surface shear stress distribution and soil wind erosion

Through wind tunnel experiments, we measured the surface shear stress (τs) on a bed surface that contained widely but uniformly spaced non-erodible ridges. We found that when the ridge spacing is larger than 10 times the height (H), the τs between two adjacent ridges could be divided into two sections. In each section, shear stress gradually increases and then decreases. The first section appears to be produced by the reverse-flow vortex that develops close behind upwind ridges and the second appears to result from airflow recovery followed by blockage by the downwind ridge. The mean surface shear stress (τs¯) of the total bed increases with increasing ridge spacing and friction velocity, and decreases with increasing ridge density. The spatial differences in τs lead to a non-uniform distribution of wind erosion between the ridges. Based on the threshold shear stress (τt) of the tested soil, we revealed a regular distribution of effective shear stress (τeff) on the sand bed, and established quantitative relationships among mean effective shear stress (τeff¯), H, ridge spacing (L), friction velocity (u*), and the threshold friction velocity (u*t) for sand entrainment: τeff¯=aLHu*-u*t2.

Numerical Study of the Hydrodynamics of Waves and Currents and Their Effects in Pier Scouring

The scour around cylindrical piles due to codirectional and opposite waves and currents is studied with Reynolds Averaged Navier–Stokes (RANS) equations via REEF3D numeric modeling. First, a calibration process was made through a comparison with the experimental data available in the literature. Subsequently, not only the hydrodynamics, but also the expected scour for a set of scenarios, which were defined by the relative velocity of the current ( U C W ), were studied numerically. The results obtained show that the hydrodynamics around the pile for codirectional or opposite waves and currents not have significant differences when analyzed in terms of their velocities, vorticities and mean shear stresses, since the currents proved to be more relevant compared to the net flow. The equilibrium scour, estimated by the extrapolation of the numerical data with the equation by Sheppard, enabled us to estimate values close to those described in the literature. From this extrapolation, it was verified that the dimensionless scour would be less when the waves and currents are from opposite directions. The U C W parameter is an indicator used to adequately measure the interactions between the currents and waves under conditions of codirectional flow. Nevertheless, it is recommended to modify this parameter for currents and waves in opposite directions, and an equation is proposed for this case.

Three-dimensional simulation of horseshoe vortex and local scour around a vertical cylinder using an unstructured finite-volume technique

A Large Eddy Simulation model is developed to simulate the hydrodynamics and scour process around a circular cylinder. The Navier-Stokes solver is based on the projection method and a second-order unstructured finite-volume method. A sigma-coordinate system is used to obtain an accurate representation of the evolution of the sediment-water interface. Bed erosion is simulated by solving the sediment continuity equation using a mass-conservating sand-slide algorithm and a bedload transport rate, which is based on a description of physical processes (Engelund & Fredsøe, 1976). Simulations of flow around a vertical cylinder for free-slip bed, rigid bed, and live-bed cases are done. The mean velocity profile and shear stress validate the accuracy of this model. Horseshoe vortex and lee-wake vortex shedding structure are simulated, and the results are thoroughly discussed in depth. The formation and the temporal development of the scour hole and other topographic bed features are successfully reproduced. The current paper reports the first known investigation of both scour evolution and coherent structure using large-eddy simulation.

Fatigue behavior of 2618-T851 aluminum alloy under uniaxial and multiaxial loadings

AA2618 aeronautical aluminum alloy has been largely used in the past, especially in well-known Concorde aircraft, developed during sixties decade. In more recent aircraft, this alloy has been largely replaced by others such as 7075 which present greater fatigue resistance. Forgotten for a time, AA2618 comes back in new aircrafts for structural parts submitted to fatigue loading at high temperature because of only a slight decrease of fatigue resistance of this alloy compared to room temperature fatigue resistance. In this paper, a complete fatigue characterization of 2618-T851 aluminum alloy is presented: fatigue tests under uniaxial tensile or torsion cyclic loadings, with mean tensile or shear stress have been realized; fatigue tests under combined tensile-torsion, in or out-of-phase have also been conducted as well as some combined tensile-torsion-internal pressure fatigue tests. All these tests covered 104–107 cycles range. At last, Crossland multiaxial fatigue criterion has been used and extended to median fatigue life domain to analyze these results.

Comprehensive shear stress analysis of turbulent boundary layer profiles

Motivated by the need for accurate determination of wall shear stress from profile measurements in turbulent boundary layer flows, the total shear stress balance is analysed and reformulated using several well-established semi-empirical relations. The analysis highlights the significant effect that small pressure gradients can have on parameters deduced from data even in nominally zero pressure gradient boundary layers. Using the comprehensive shear stress balance together with the log-law equation, it is shown that friction velocity, roughness length and zero-plane displacement can be determined with only velocity and turbulent shear stress profile measurements at a single streamwise location for nominally zero pressure gradient turbulent boundary layers. Application of the proposed analysis to turbulent smooth- and rough-wall experimental data shows that the friction velocity is determined with accuracy comparable to force balances (approximately 1 %–4 %). Additionally, application to boundary layer data from previous studies provides clear evidence that the often cited discrepancy between directly measured friction velocities (e.g. using force balances) and those derived from traditional total shear stress methods is likely due to the small favourable pressure gradient imposed by a fixed cross-section facility. The proposed comprehensive shear stress analysis can account for these small pressure gradients and allows more accurate boundary layer wall shear stress or friction velocity determination using commonly available mean velocity and shear stress profile data from a single streamwise location.

Abstract 146: Glomerular Capillary Hypertrophy is Insufficient to Mitigate Mechanical Stresses in 5/6 Nephrectomy: A Modeling Study

The 5/6-nephrectomy (5/6 Nx) model of renal mass reduction shows an increased glomerular pressure (ΔP) and afferent plasma flow (Q a ) in the remaining glomeruli. These hemodynamic consequences are assumed to increase glomerular capillary wall circumferential hoop stress (HS) and shear stress (SS), respectively. Due to a lack of anatomically-accurate mathematical models of the glomerulus, the actual magnitudes of SS and HS in the entire network of glomerular capillaries remain uncertain in 5/6-Nx. These forces are of significance due to the sensitivity of endothelial cells to SS and podocytes to HS. We developed a mathematical model of blood flow through an anatomically-accurate rat glomerular capillary network to estimate the magnitudes of SS and HS on the glomerular capillary walls in 5/6-Nx. Filtration rates, wall HS and wall SS were calculated for each capillary segment of the network based on parameters obtained from a micropuncture study using normal rats and rats with 5/6-Nx (Kasiske, Bertram L., et al. Circ. Res. 62.2: 367-374. (1988)). In this study, 5/6-Nx increased Q a and ΔP by 174.8% and 19.0%, respectively. To simulate glomerular capillary hypertrophy in 5/6-Nx, the capillary diameters were all increased by 16.1%. Using these data, the Young-Laplace equation was used to calculate HS in each capillary, and SS was calculated assuming Poiseuille flow with blood viscosity scaled based on vessel diameter and hematocrit. Taking into account an increase in diameter of the glomerular capillaries, the model predicted mean SS values of 48.1 dynes/cm 2 in control and 79.4 dynes/cm 2 in 5/6-Nx. The increase in diameter of the glomerular capillaries was not sufficient to prevent the increase in SS, a finding in contrast to the previous experimental analysis which suggested normalization of SS. The increase in glomerular capillary diameter increased mean HS from 144.1 kPa to 199.2 kPa. This study demonstrates that this increase in diameter was not sufficient to mitigate the increased SS in 5/6-Nx and contributes to a significantly increased HS. These increased mechanical stresses on the glomerular capillaries may play a causative role in the progression of glomerular injury in 5/6-Nx thus leading to chronic kidney failure.

Multiaxial high-cycle fatigue failure of 30CrMnSiA steel with mean tension stress and mean shear stress

Experiments had been performed to investigate the effect of the mean tension stress and mean shear stress on the multiaxial fatigue failure of 30CrMnSiA steel. The crack growth path was observed under a metallographic microscope. The stage I cracks were always initiated on the MSSA planes and propagated approximately 20–100 μm for the different load conditions. The stage II crack propagated approximately 400–1000 μm along the MN plane for in-phase loading. The stage II crack initially propagated along the MN plane and quickly deviated from it for 90° out-of-phase loading. Crack initiation and early propagation (<500 μm) occupied more than 70% of the fatigue failure life. Both mean shear stress and mean tension stress reduced the fatigue life. In addition, deficiencies of the critical plane criteria based on the MSSA plane were discussed and more attention should be paid to the effect of mean shear stress.

Mean Velocity and Shear Stress Distribution in Floating Treatment Wetlands: An Analytical Study

AbstractFloating treatment wetlands (FTWs) are efficient at wastewater treatment; however, data and physical models describing water flow through them remain limited. A two‐domain model is proposed dividing the flow region into an upper part characterizing the flow through suspended vegetation and an inner part describing the vegetation‐free zone. The suspended vegetation domain is represented as a porous medium characterized by constant permeability thereby allowing Biot's Law to be used to describe the mean velocity and stress profiles. The flow in the inner part is bounded by asymmetric stresses arising from interactions with the suspended vegetated (porous) base and solid channel bed. An asymmetric eddy viscosity model is employed to derive an integral expression for the shear stress and the mean velocity profiles in this inner layer. The solution features an asymmetric shear stress index that reflects two different roughness conditions over the vegetation‐induced auxiliary bed and the physical channel bed. A phenomenological model is then presented to explain this index. An expression for the penetration depth into the porous medium defined by 10% of the maximum shear stress is also derived. The predicted shear stress profile, local mean velocity profile, and bulk velocity agree with the limited experiments published in the literature.

Fluctuation in shear rate, with unaltered mean shear rate, improves brachial artery flow-mediated dilation in healthy, young men.

Increase in mean shear stress represents an important and potent hemodynamic stimulus to improve conduit artery endothelial function in humans. No previous study has examined whether fluctuations in shear rate patterns, without altering mean shear stress, impacts conduit artery endothelial function. This study examined the hypothesis that 30-min exposure to fluctuations in shear rate patterns, in the presence of unaltered mean shear rate, improves brachial artery flow-mediated dilation. Fifteen healthy men (27.3 ± 5.0 yr) completed the study. Bilateral brachial artery flow-mediated dilation was assessed before and after unilateral exposure to 30 min of intermittent negative pressure (10 s, -40mmHg; 7 s, 0 mmHg) to induce fluctuation in shear rate, while the contralateral arm was exposed to a resting period. Negative pressure significantly increased shear rate, followed by a decrease in shear rate upon pressure release (both P < 0.001). Across the 30-min intervention, mean shear rate was not different compared with baseline (P = 0.458). A linear mixed model revealed a significant effect of time observed for flow-mediated dilation (P = 0.029), with exploratory post hoc analysis showing an increase in the intervention arm (∆FMD +2.0%, P = 0.008), but not in the contralateral control arm (∆FMD +0.5%, P = 0.664). However, there was no effect for arm (P = 0.619) or interaction effect (P = 0.096). In conclusion, we found that fluctuations in shear patterns, with unaltered mean shear, improves brachial artery flow-mediated dilation. These novel data suggest that fluctuations in shear pattern, even in the absence of altered mean shear, represent a stimulus to acute change in endothelial function in healthy individuals. NEW & NOTEWORTHY Intermittent negative pressure applied to the forearm induced significant fluctuations in antegrade and retrograde shear rate, while mean shear was preserved relative to baseline. Our exploratory study revealed that brachial artery flow-mediated dilation was significantly improved following 30-min exposure to intermittent negative pressure. Fluctuations in blood flow or shear rate, with unaltered mean shear, may have important implications for vascular health; however, further research is required to identify the underlying mechanisms and potential long-term health benefits.

Does habitual endurance exercise protect endothelial function against acute exposure to oscillatory shear stress?

Introduction: Acute exposure to increases in oscillatory shear stress (increased retrograde shear stress and decreased mean shear stress) reduces flow-mediated dilation (FMD). This impairment may be mediated via increased oxidative stress. Habitual endurance exercise training results in increased antioxidant protection. However, it is currently unknown whether these adaptations protect against oscillatory shear stress-induced impairments in FMD.&#x0D; Purpose and Hypothesis: The purpose of this study is to determine whether lower limb endurance-trained athletes have protection against oscillatory shear stress-induced impairments in FMD compared to sedentary individuals. It is hypothesized that athletes will have a preserved FMD after an acute oscillatory shear stress intervention, compared to their sedentary counterparts.&#x0D; Methods: Healthy, young adult volunteers (18-29 years old) will be screened for physical activity (PA) through a physical activity recall questionnaire. 12 sedentary individuals (&lt;3h of structured PA/week) and 12 lower limb endurance athletes will be recruited to participate. All participants will complete a VO2 peak test to objectively measure cardiorespiratory fitness. Participants will visit the laboratory twice in the same week for vascular testing. Both 90-minute visits will begin with 45 minutes of supine rest, followed by a brachial artery FMD test before and after 30 minutes of either imposed oscillatory shear stress (forearm cuff inflated to 70 mmHg) or a 30 min rest period (control). &#x0D; Significance: This will be the first study to investigate whether endurance-trained athletes are resistant to oscillatory shear-stress induced impairments in endothelial function. This will provide insight into mechanism contributing to the vasoprotective effects of habitual endurance exercise.

Full stress tensor measurement using fluorescence spectroscopy

Photoluminescent spectral peak positions are known to shift as a function of mechanical stress state. This has been demonstrated at macroscales to determine mean stress and mesoscales to determine mean stress and a quantity related to shear stress. Here, we propose a method to utilize traction-free surface conditions and knowledge of material orientation to solve for two in-plane displacement fields given two measured spectral peak positions measured at a grid of points. It is then possible to calculate the full stress tensor at each measurement point. This is a significant advancement over the previous ability to measure one or two stress quantities. We validate the proposed method using a simple, two-grain geometry and show that it produces the same mean stress and shear stress measure as the existing direct method. We also demonstrate determination of the full stress field in a polycrystalline alumina specimen.

Glomerular Capillary Hypertrophy in the Diabetic Rat Normalizes Wall Shear Stress: A Modeling Study

Diabetes mellitus (DM) reduces renal hemodynamic autoregulation, leading to increased glomerular pressure (ΔP) and afferent plasma flow (Qa) which is assumed to increase glomerular capillary wall shear stress (SS). However, glomerular capillaries undergo hypertrophy in DM, causing an increase in capillary diameter that would theoretically reduce capillary wall SS (Seyer‐Hansen, Kjartan. Kid. Int. 23.4 (1983): 643–646.). The actual magnitudes of SS in the glomerular capillaries have not been estimated in DM and are of significance because in response to increased SS, endothelial cells increase expression of adhesion molecules and growth factors associated with glomerulopathy.We developed a mathematical model of blood flow through an anatomically‐accurate rat glomerular capillary network to estimate the magnitudes of SS on the glomerular capillary walls in DM and control. Individual filtration rates and wall SS were calculated for each capillary segment of the network based on values of Qa, ΔP and single nephron GFR (SNGFR) obtained from micropuncture studies. To validate mechanical predictions of our model, we compared our calculated SS magnitudes to results from intravital imaging studies of blood flow in rat glomeruli (Ferrell, Nicholas, et al. Am. J. Physiology‐Renal 308.6 (2015): F588‐F593.). To calculate SS magnitudes in the rat glomerulus in control and DM, we performed simulations with parameters obtained from micropuncture studies using normal rats and rats with streptozotocin induced Type I diabetes. In this study, DM increased Qa and ΔP by 74.6% and 33.3%, respectively but reduced the filtration coefficient (Kf) such that filtration fraction (FF) was maintained (Zatz, Roberto, et al. J. clin. Inv. 77.6 (1986): 1925–1930).The model was calibrated using an algorithm previously described (Remuzzi, Andrea, et al. Am. J. Physiology‐Renal 263.3 (1992): F562‐F572). Our model's calculated mean glomerular capillary wall SS was within 10% of the mean SS predicted using intravital imaging, validating our model for use in predicting mechanical aspects of blood flow in the glomerulus. Our simulations demonstrated a wide variance in SS throughout the glomerular capillary network, consistent with previous modeling results. Using parameters from micropuncture experiments and taking into account hypertrophy of the glomerular capillaries, the model predicted mean SS values of 42.1 dynes/cm2 in control and 42.3 dynes/cm2 in DM.We have developed and validated an anatomically‐accurate mathematical model of glomerular filtration for use in predicting functional and mechanical results of varied glomerular pressure, afferent plasma flow and Kf. Using this model, we demonstrated that hypertrophy of the capillaries normalizes capillary wall SS in DM, which may be a protective mechanism limiting the increase in SS and the consequent glomerular injury.Support or Funding InformationThis work was supported by the National Institute of General Medical Sciences IDeA Program (CoBRE P30GM103337) (principal investigator: L. G. Navar) O. Richfield is a graduate student supported by NSF IGERT Grant NSF DGE‐1144646.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.