LDA Measurements Research Articles

Robot-LDA Plane Measurements And Smoke Investigations On A 30° Inclined Flat Plate In An Open Wind Channel With And Without Plasma Actuation Effect

Active flow control is a relatively new approach to influence the velocity vector field for plane airfoils or process engineering applications with a plasma source. The goal is to positively effect the point of separation to increase the lift/drag ratio or increase separation efficiency and to reduce pressure drop. In the presented study two approaches, the Robot-LDA measurements and smoke investigations, are chosen to find out whether the plasma source has an effect on the velocity vector field on a 30°inclined flat plate and the separation point. A flow rate of 250 m³/h resulting in a Reynolds number of 100 000 is chosen, since this is typical for already presented results within the field of plasma source investigations. With Robot-LDA in total 825 measurements points of the axial wind channel velocity components are captured twice, with and without activated plasma source. The measurement plane was set 80 mm x 50 mm orthogonal to the flat plate in the middle of the wind channel axis. The plasma source was powered with 14 kVp−p and 5 kHz. Due to stability of the plasma actuator, the LDA measurements were subdivided into eight regions. For the same configurations smoke investigations are performed. A chromium-nickel wire with a diameter of 0.213 mm is heated by an electronic circuit including capacitor and power source to vaporize liquid paraffin. The flow field is captured by a highspeed camera. Robot-LDA measurement results show a free-stream axial wind channel velocity component of about 15 m/s. In the shadow region of the 30°inclined flat plate a recirculation zone is found due to negative velocity components. At a distance up to 12 mm close to the plat plate, wall reflections dominated and to find valid LDA measurement results were not possible. With and without activated plasma source velocity differences between -0.5 m/s and 0.5 m/s are found. The biggest velocity differences are in the region of 15 mm to 45 mm relative to the tip of the inclined flat plate. For post-processing purposes, the 3D wind channel geometry and the Robot-LDA measurement results are loaded in ParaView 5.10.1. Smoke investigations show that the plasma source minimally attach the flow to the flat plate. This effect is higher with smaller flow rates (50 m³/h) than with 250 m³/h. Robot-LDA and smoke measurement results are promising that flow influence due to plasma has potential in various applications in future.

Hybrid LES/RANS simulations of a 90° pipe bend using different CFD solvers

In this study, the performance of several RANS and hybrid LES/RANS turbulence models along with different CFD solvers (ANSYS Fluent, OpenFOAM and RapidCFD) is tested in terms of their ability to reproduce the flow downstream of a 90° pipe bend. The focus is on the temporal mean profiles downstream of the bend up to approximately 31 times the pipe's diameter D. The turbulence models' accuracy is evaluated by means of performance indicators and flow profiles in comparison to LDA measurements. The results demonstrate that the use of RANS models is suitable as long as the location of interest is in the vicinity of the bend up to approximately 10 D downstream of the bend. With increasing distance, the accuracy of the RANS models decreases, and the use of hybrid LES/RANS models is recommended.Three hybrid LES/RANS models are tested: the stress-blended eddy simulation (SBES) model as well as the Spalart-Allmaras-based and the k-omega SST-based improved delayed detached eddy simulation (IDDES) models. All three models show enhanced results for a distance to the bend >10 D. Additionally, it is found that in this geometry configuration, the IDDES models require a transient inlet. The flow separation due to the redirection inside the bend is too weak to generate turbulent fluctuations and a fast transition to full LES mode in the separation region. Due to the turbulent excitation at the inlet, the RANS region downstream of the bend is distinctly reduced, resulting in an enhanced performance of the hybrid IDDES models.

Flow Dynamics Between Two Car Models: Influence Of The Intervehicle Distance

Air pollution is a crucial issue since it is one of the major causes for worldwide deaths. Car drivers and passengers are daily exposed to high level of pollutant concentrations. The particles emitted from the tailpipe can disperse in the wake of the vehicle and then infiltrate the following car c abin. It has been demonstrated that the dynamics of such particles are highly affected by the properties of the flow downstream the emitting vehicle. In the present paper, the flow characterization in the wake of a simplified car model followed by a second vehicle is performed. Reduced-scaled Ahmed bodies are used. The upstream velocity is set to U∞ = 14.3 m/s, corresponding to a Reynolds number based on the simplified model’s height ( hc = 54 mm) of Re = 49500. Two leading vehicles with two different rear slant angles (φ = 0°, 25°) are considered. Two sets of experiments are carried out, one in the wind tunnel at ESTACA and the other in the wind tunnel at CORIA’lab. In the first measurement campaign, 2D LDV is used and six inter-vehicle distances ranging from d = 0.93 hc to 5.56 hc are considered and presented. The ITTT (Interarrival Time and Transit Time) method is applied to LDV data in order to ensure reliable results. Mean and turbulent properties of the wake between the two vehicles are described. The role of the rear slant angle is highlighted. A critical distance above which the followed vehicle has an insignificant influence on the flow topology downstream of the leading vehicle is identified. For further details, and taking into consideration the first results (from LDV measurements), Stereo-PIV measurements are used to get access to the three components of the velocity. Due to time constraint, only three inter-vehicle distances are discussed in this paper (0.93 hc, 1.85 hc and 3.70 hc). The SPIV results validate those obtained from LDV measurements and provide complementary information. The sensitivities of the bi-stability of the transverse velocity to the short inter-vehicle distance (0.93 hc) and to the slant rear angle are investigated. SPIV measurements are then correlated with LDA measurements taking into account this behavior. These measurements are completed by further measurements of concentrations of the exhausted particles from the tailpipe.

Statistical interpretation of LDA measurements in naturally developing turbulent drag-reducing flow using invariant theory

Turbulent drag reduction by an extremely diluted aqueous solution of polyacrylamide was studied in a fully developed plane channel flow under non-tripped flow conditions allowing the natural development of turbulence presumably from the initially laminar like a flow state. Using laser-Doppler anemometry, all components of the Reynolds stress tensor were measured. This permitted the determination of the turbulence anisotropy and independent invariants of the anisotropy tensor. Introducing a measure for the departure of the Reynolds stress tensor from the statistically axisymmetric state that ensures laminarity, fundamental insights relating the origin of turbulence and turbulent drag reduction were analyzed in light of the measured results and existing databases of direct numerical simulations. The chief mechanism relevant to the onset of turbulence and turbulent drag reduction deduced from analytic considerations involving only kinematic constraints was confirmed by the experimental data. Parametrization of the drag reduction effect in terms of the Deborah number based on turbulence quantities evaluated at the wall supports the deduction of the polymer-turbulence interaction in terms of the elastic properties of the polymer and the near-wall turbulence structure.

Numerical study on abnormal airflow patterns and particle deposition characteristics in the realistic HUA model with pharyngeal obstruction

The effects of morphological variation of pharynx on abnormal airflow patterns and particle deposition characteristics in the realistic OSA HUA model with pharyngeal obstruction are numerically studied using the LES-DPM. Firstly, the LDA measurements on airflow patterns in the HUA model are executed to verify the reliability of LES, and the numerical simulations on particle deposition behaviors in a simplified human throat are conducted to validate the reliability of DPM. Afterwards, the airflow patterns, including velocity field, pressure field and shear stress field, and the regional/total particle deposition features with various particle sizes (0.5–10 μm) at different respiration intensities (16.8–60 L/min) inside HUA model are examined. The fitting formula among total deposition efficiency, particle size and respiratory intensity is eventually established. The results lead to the following conclusions: (1) The morphological variation of pharynx significantly affects the abnormal airflow patterns and particle deposition features. Pharyngeal obstruction not only induces abnormal high intensity of turbulent flow, negative pressure and positive shear stress, but also causes abnormal high local deposition efficiency in the nasal cavity and larynx. (2) The enhancement of respiration intensity greatly aggravates the abnormal airflow patterns. With the increasing of respiration intensity, the jet-flow, reversed-flow, negative pressure and positive shear stress all noticeably strengthen. Rapid medical diagnosis on airway operation can be realized by judging the maximal negative pressure and positive shear stress. (3) The increments of both particle size and respiration intensity evidently augment the abnormal particle deposition features. With the rising of particle size and respiration intensity, the total particle deposition efficiencies obviously improve. However, inertial impaction is the essential mechanism for abnormal deposition characteristics, which is more important than that of turbulence intensity. This work not only would help to understand the pathophysiology of OSA disease, but also would assess both the health impacts of inhaled particles and the therapeutic efficacy of inhaled drug aerosols in the airways of OSA patients.

High resolution LDA measurements in transitional oblique shock wave boundary layer interaction

Spatial development of a transitional Oblique Shock Wave Interaction at Mach 1.68 is presented. This type of flow is characterised by very small length scales (boundary layer thickness is smaller than 1mm), high velocities, reverse flows and a wide range of velocity fluctuations along the transition process. Unsteady velocity fields have been obtained using a high spatial resolution Laser Doppler Anemometry system, allowing quantitative measurements of the velocity fluctuations down to $$y/\delta =0.1$$ . A model to take into account the finite size of the probe volume on the mean and RMS velocity measurements is used and applied to the present measurements. Finally, the amplification of the velocity fluctuations along the transitional separated shear layer is described.

Assessment of the transition k-k-ω model application to transitional oscillatory pipe flows.

The flow transition from laminar to turbulent inside of typical thermoacoustic devices influences the heat-exchange capacities of these devices and dramatically impacts overall performances as well. A few measurements [Eckmann and Grotberg (1991), J. Fluid Mech. 222, 329-350; Hino, Sawamoto, and Takasu (1976). J. Fluid Mech. 75, 193-207] and direct simulations [Feldmann and Wagner (2012). J. Turbul. 13(32), 1-28; Feldmann and Wagner (2016a). New Results in Numerical and Experimental Fluid Mechanics X, pp. 113-122] were reported that describe the transitional oscillatory flows; however, almost no turbulence model has been developed that enables accurate detection and characterization of the reported intermittent turbulent fluctuations. The present work aims to assess the applicability of the k-kL-ω transition model to transitional oscillatory pipe flows. A sinusoidal pressure gradient is introduced into ANSYS finite-volume solver for flow field simulation at different acoustic frequencies, while a friction Reynolds number of 1440 is retained. The stationary turbulent and the laminar oscillatory pipe flows are first considered for validation and model calibration against published LDA measurements [Durst, Kikura, Lekakis, Jovanovic, and Ye (1996). Exp. Fluids 20, 417-428] and DNS results [Feldmann and Wagner (2012). J. Turbul. 13(32), 1-28] in addition to the Sexl's laminar-flow theory [Sexl (1930). Zeitschrift Phys. 61(5), 349-362]. Investigation of the total fluctuation kinetic energy of transitional oscillations reveals the appearance of intermittent fluctuations within the near-wall region at Wo = 13 during deceleration, while fully turbulent oscillations are predicted in the entire pipe domain at Wo = 5. Although the present results are qualitatively in good agreement with reported experimental [Eckmann and Grotberg (1991). J. Fluid Mech. 222, 329-350] and DNS findings [Feldmann and Wagner (2012). J. Turbul. 13(32), 1-28], the velocity profiles show poor agreement with corresponding DNS data during flow acceleration at Wo = 5.

Aerodynamic assessment of the cycloidal rotor fan

This paper presents numerical and experimental testing of a cycloidal rotor fan (CRF). The tested cyclorotor is made of four NACA0012 profile blades. CFD calculations using the Ansys CFX® tool and the LDA measurement technique are performed to determine the fan performance for different operating parameters, i.e. rotational speed and the rotor blade maximum swing angle values. One initial position of the blades corresponding to one air-flow direction is considered only. The comparison between the numerical results and the experimental LDA measurements is satisfactory and encouraging further investigation.

Wpływ kształtu cząstek ilastych na wyniki analiz granulometrycznych gruntów spoistych

Laser diffraction particle sizing is an alternative method to determine grain size analysis in soils. However, for particle with high shape anisotropy LDA measurements usually produce different results than traditional hydrometric methods (HM), based on Stokes equation. The article contains the results of analyzes of Neogene clays characterized by significant lithological differentiation in regard to participation the clay fraction particles. The research was conducted for the clay samples taken in Bydgoszcz. A set of equations to transform LDM results to hydrometric results was proposed.

Validation of SIV measurements of turbulent characteristics in the separation region

Temporally and spatially resolved 2D measurements are important for the studies of complex turbulent flows. The recently developed SIV technique (Smoke Image Velocimetry), which is superior to PIV in some cases, can be used for this purpose. SIV validation results are presented for the steady turbulent backward-facing step flow measurements. Velocity profiles and Reynolds stress profiles are given for the regions of oncoming flow, reverse flow, flow reattachment and relaxation. The Reynolds number based on the step height and oncoming flow velocity at the boundary layer edge was Reh = 4834. The obtained data have been compared to LDA measurements and DNS.

CFD analyses of the rod bowing effect on the subchannel outlet temperature distribution

Abstract In the Loviisa 1 and 2 nuclear power plants the subcooling margin of the hottest subchannel of the fuel assembly is monitored. The temperature of the coolant in the hottest subchannel is limited to the constant saturation temperature. Bending of the fuel rods occurs during normal operation due to the differences in the heat profiles of the rods. The coolant temperature will rise more in the subchannel with smaller flow area due to the bending and this has to be taken into account in the safety margin of subchannel enthalpy rise. Computational Fluid Dynamics (CFD) simulations are used to estimate how much the estimated maximum bow of a rod affects the temperature rise of the subchannel. The quantitative uncertainty of the predicted enthalpy rise in fuel bundle subchannel is estimated based on the uncertainty of modelling of mixing between subchannels. The measured turbulence quantities from LDA measurements of cold test assembly made in 1990s in Fortum are compared with CFD results to give uncertainty estimation for turbulence, which is further used for uncertainty estimation of mixing and simulated subchannel enthalpy rise.

APPLICATION OF SMOOTHED PARTICLE HYDRODYNAMICS (SPH) IN NEARSHORE MIXING: A COMPARISON TO LABORATORY DATA

A weakly compressible smoothed particle hydrodynamics (WCSPH) method is used to simulate the nearshore flow hydrodynamics. The wave induced dispersion and diffusion are determined for monochromatic waves with significant wave height of 0.12 m and the wave period of 1.2 sec (Sop=5%) based on WCSPH wave dynamics. The hydrodynamics of WCSPH model are compared to the laboratory results obtained from series of LDA measurements. The overall mixing coefficients across the nearshore are determined from WCSPH hydrodynamics. The mixing coefficients obtained are compared with the values determined from a series of fluorometric studies performed in a large-scale facility in DHI, Denmark. The results show that the wave profiles are in good agreement with the experimental data. The WCSPH model is proven to be well capable of estimating the dispersion across the nearshore.

Experimental data and numerical predictions of a single-phase flow in a batch square stirred tank reactor with a rotating cylinder agitator

Single-phase flows in stirred tank reactors have useful characteristics for a wide number of industrial applications. Usually, reactors are cylindrical vessels and complex impeller designs, which are often highly energy consuming and produce complicated flow patterns. Therefore, a novel configuration consisting of a square stirred tank reactor is proposed in this study with potential advantages over conventional reactors. In the present work hydrodynamics and turbulence have been studied for a single-phase flow in steady state operating in batch condition. The flow was induced by drag from a rotating cylinder with two diameters. The effects of drag from the stirrer as well as geometrical parameters of the system on the hydrodynamic behavior were investigated using Computational Fluids Dynamics (CFD) and non-intrusive Laser Doppler Anemometry, (LDA). Data obtained from LDA measurements were used for the validation of the CFD simulations, and to detecting the macro-instabilities inside the tank, based on the time series analysis for three rotational speeds N = 180, 1000 and 2000 rpm. The numerical results revealed the formation of flow patterns and macro-vortex structures in the upper part of the tank as consequence of the Reynolds number and the stream discharge emanated from the cylindrical stirrer. Moreover, increasing the cylinder diameter has an impact on the number of recirculation loops as well as the energy consumption of the entire system showing better performance in the presence of turbulent flows.

Experimental investigation of turbulent flames in uniform dispersions of ethanol droplets

A turbulent flame in an ethanol droplet-laden uniform mixture is investigated at overall equivalence ratios (ϕov) of 0.62, 0.72 and 0.82, using a piloted Bunsen burner. Imaging of OH* chemiluminescence and simultaneous imaging of OH PLIF and Mie scattering, both at 5 kHz, and imaging of CH2O-fuel PLIF at 5 Hz, were used to obtain instantaneous and time-averaged images, temporal sequences and 2-D estimates of flame surface density and curvature. 1-D PDA and LDA measurements were used to obtain droplet size and velocity statistics. At ϕov = 0.62, the flame takes a cylindrical shape, and changes to a cone shape with increasing fuel loading to obtain higher ϕov. Larger droplets are generally observed to have lower average and RMS axial velocities than smaller droplets. Profiles of droplet size distributions indicate a decreasing droplet number density downstream together with a shift to larger droplet diameters. The flame structure is observed to be relatively smooth at locations near the burner exit, and becomes more contorted with distance downstream. In general, droplets are observed to coincide with low-to-intermediate regions of OH. Occasionally, droplets appear to penetrate the flame front, and are detected in regions of intermediate-to-high OH. This occurs particularly at the downstream locations where the flame closes across the jet, with no significant averaged droplet penetration observed past 2 mm in the direction normal to the flame front. Measurements show a gradual reduction in flame surface density and higher flame front curvature with both distance downstream and increasing fuel loading. Estimates of the average droplet evaporation rate increase with both distance downstream and ϕov, as droplets appear in higher mean progress variable regions. The measurements reported here are useful for model validation of flame propagation in dilute sprays.

A new model of cavern diameter based on a validated CFD study on stirring of a highly shear-thinning fluid

Results of numerical simulations of momentum transfer for a highly shear-thinning fluid (0.2% Carbopol) in a stirred tank equipped with a Prochem Maxflo T type impeller are presented. The simulation results were validated using LDA data and both tangential and axial force measurements in the laminar and early transitional flow range. A good agreement between the predicted and experimental results of the local fluid velocity components was found. From the predicted and experimental values of both tangential and axial forces, the power number, Po, and thrust number, Th, were also calculated. Values of the absolute relative deviations were below 4.0 and 10.5%, respectively, for Po and Th, which confirms a satisfactory agreement with experiments. An intensive mixing zone, known as cavern, was observed near the impeller. In this zone, the local values of fluid velocity, strain rate, Metzner–Otto coefficient, shear stress and intensity of energy dissipation were all characterized by strong variability. Based on the results of experimental study a new model using non-dimensional impeller force number was proposed to predict the cavern diameter. Comparative numerical simulations were also carried out for a Newtonian fluid (water) and their results were similarly well verified using LDA measurements, as well as experimental power number values.

CFD modelling of entropy generation in turbulent pipe flow: Effects of temperature difference and swirl intensity

This article extends the recent study by Saqr and Wahid (Applied Thermal Engineering 70 (2014) 486–493) on the criteria of heat transfer enhancement in swirl pipe flow based on the entropy generation minimization principle. The effects of wall–fluid temperature difference (ΔT) and swirl intensity (Sn) on entropy generation are considered in the present work. A Computational Fluid Dynamics (CFD) model of non-isothermal swirl pipe flow was developed, validated with established LDA measurements, and then used to study the Nusselt (Nu), entropy augmentation (Ns) and Bejan (Be) numbers in 77 different scenarios related to swirl-enhanced heat exchangers. Critical values of ΔT and Sn that correspond to unity Ns were identified. Then, based on the CFD results, two computer codes were developed in MATLAB software to correlate Ns and Be as functions of ΔT and Sn. These computer codes are openly provided in this article's appendix in order to contribute to the design and optimization tools of swirl-enhanced heat exchangers.

Large eddy simulation of a pitched blade impeller mixed vessel – Comparison with LDA measurements

This study deals with a large eddy simulation (LES) of the single-phase turbulent flow in a fully baffled mixed vessel stirred by a pitched six-blade impeller. The ANSYS FLUENT 15.7 commercial CFD programme was employed. The LES turbulent model is used with the dynamic Smagorinsky–Lilly model. The Werner–Wengle wall function is used to cope with the requirements of near the wall cell size of the LES model. The sliding mesh (SM) model was used for simulating the impeller movement. The results of the simulations are compared with experimental data obtained by previous LDA measurements of the radial profiles of the axial component of the ensemble averaged mean velocity in the impeller discharge flow. The volume flow rates and the flow rate criteria were calculated from these velocity profiles, and were compared with the flow rates determined from the horizontal vessel cross section from simulation.

Laser-Doppler measurements of the turbulent mixing of two rectangular water jets impinging on a stationary pool

Turbulent mixing of parallel jet flows has broad engineering applications. For example, in Gen. IV conceptual nuclear reactors, high-temperature flows mix in the lower plenum before entering the secondary cooling system. The mixing condition needs to be accurately estimated and fully understood. In addition, massive computational works involved in the design process necessitate high-fidelity experimental data sets for benchmarking simulation results.The purpose of this study is to use laser Doppler anemometry, a non-intrusive measuring technique, to evaluate the mixing characteristics of two submerged parallel jets issuing from two rectangular channels. The jets with a small spacing ratio of 3.1 were at room temperature. Flow characteristics including distributions of mean velocities, turbulence intensities, and Reynolds stresses were studied for the cases with equal and non-equal discharge velocities. The merging point (MP) was found to be between y/a=1.72 and y/a=3.45. The combining point (CP) was at y/a=15.52. The Reynolds shear stress, a measure of the intensity of momentum transfer, reached its maximum after the merging point. An uncertainty analysis indicated that the average standard deviations of the streamwise mean velocity U and turbulence intensity Urms at all locations in the five days’ measurements were 1.5% and 1.6%, respectively. Spectral analyses including fast Fourier transform, power spectral density estimation and continuous wavelet transform revealed the scale and the evolution in time of varied-size eddies in the mixing region of the flow. Repeating flow structures were observed in different time segments.The experimental data obtained from the LDA measurements of the averaged quantities and transient are not only valid for benchmarking steady-state numerical simulations using turbulence models to solve RANS equations but they also enlarge the database of the experimental data for twin jets.

Conditional analysis of turbulent premixed and stratified flames on local equivalence ratio and progress of reaction

Previous studies on the Cambridge/Sandia stratified burner have produced a comprehensive database of line Rayleigh/Raman/CO LIF measurements of scalars, as well as LDA and PIV measurements of velocity, for flames under non-uniform mixture fraction, under moderate turbulent conditions where the ratio of the turbulent velocity fluctuations to the laminar flame speed is of order 10. In prior work, we applied multiple conditioning methods to demonstrate how local stratification increases the levels of CO and H2, relative to the corresponding turbulent premixed flame, and enhances surface density function (SDF) and scalar dissipation rate of progress of reaction (SDR), based on extent of temperature rise, at a particular location in the flame where the mixing layer and flame brush cross. In the present study, we examine the global features of selected flames at all locations, by obtaining probability density functions (PDFs) for species concentrations, SDRs, and SDFs, conditioned on local equivalence ratio and location in the flame brush throughout the domain.We find that for most cases, species profiles as a function of temperature are well represented by laminar flame relationships at the local equivalence ratio, with some deviations attributable to either differential diffusion near the flame base and local stratification effects further downstream where the flame brush crosses the mixing layer. In particular, CO2 is significantly affected by differential diffusion, and CO and H2 by stratification. However, the stratification effects on the species are relatively minor when conditioned on local equivalence ratio, a simplifying result in the context of modeling.Measurements of the gradient of progress of reaction and scalar dissipation rates, conditioned on local equivalence ratio, show that the thermal zone of the flame is thickened by turbulence: the mean SDF and SDR values are in general lower than those of unstrained laminar flames. The effect is greater under rich conditions, with conditional mean SDR decreasing to less than half of the corresponding laminar value. The extent of flame thickening is the same in the premixed as the stratified case, once the stratified measurements are conditioned on the same equivalence ratio.

Enhanced Computational Fluid Dynamics Modeling and Laser Doppler Anemometer Measurements for the Air-Flow in an Aero-engine Front Bearing Chamber—Part II

A detailed computational study of the air-flow through the outer gap of the front bearing of an aero-engine is presented. The reason to carry out this study was to understand the flow through the bearing as a function of the operational parameters of the engine, which was necessary for the modeling of the flow in the whole bearing chamber. The complex geometry and the size of the bearing gap relative to the overall dimensions of the bearing chamber and the need for very precise and detailed information of the effect on the flow within the chamber of the bearing operational parameters, prohibited the solution of the flow through the gap together with the rest of the bearing chamber. A 3D modeling of the flow through the outer bearing gap, which included a section of the ball bearing, was performed. Functions relating the pressure drop of the air coming through the bearing gap and the tangential component of velocity of the air exiting the bearing region, to the mass of air through the gap of the ball bearing and the rotational speed of the shaft were developed. The effect of the lubrication oil within the bearing was modeled as an anisotropic porous medium with a predefined law. In order to acquire in a mathematical form the above relationships a series of computational runs were performed. These relationships, in the form of second order curves, were subsequently introduced to the model of the bearing chamber as described by Aidarinis and Goulas (2014, “Enhanced CFD Modeling and LDA Measurements for the Air-Flow in an Aero Engine Front Bearing Chamber (Part I),” ASME Paper No. GT2014-26060). The constants of the relationships were derived through comparisons of the calculations with the experimental data. From the analysis, it was concluded that the pressure drop across the bearing increases with the square of the rotational speed of the shaft with the mass flow of air through the ball bearing as a parameter and vice versa. For this particular ball bearing, there is a region where, for any combination of rotational speed of the shaft and pressure drop through the bearing, there is no flow of air through the bearing. In this paper the detailed modeling methodology, the computational flow field, the boundary conditions and finally the results are presented and discussed.