Fluid Flow Visualization Research Articles

Digital core on a chip: Surfactant flooding in low-permeability reservoir

The development of hard-to-recover reserves every year requires ever-more-innovative industrial and laboratory approaches for efficient production of hydrocarbons. Oil industry has recently turned to the use of microfluidic technology to investigate the flow paths and interactions of reservoir fluids under high pressures and temperatures. The present study describes elaboration of a digital core on a chip, i.e. a microfluidic chip with the structure that replicates the void space of a selected reservoir and is designed based on the computed tomography images of core samples. Similarity of core samples and 2D generated structure was controlled through average pore diameter and structure morphology. The manufactured micromodels were used for surfactant compositions screening aiming to demonstrate the technology capabilities for further testing of various enhanced oil recovery (EOR) chemicals.Thus, several surfactants were examined in bulk employing standard screening procedures (stability evaluation, interfacial tension (IFT) measurements and phase behavior test with oil), and then were investigated in transparent microfluidic chips. Visualization of fluid flow in the porous structure is a primary advantage of microfluidics application for EOR. Hence, surfactant coreflooding-on-a-chip enabled correlation of IFT behavior of various surfactants with recovery efficiency, fast detection of in-situ emulsification and fluid flow distribution analysis in the porous media. Generally, symbiosis of two advanced technologies, i.e. microfluidics and digital core modeling, facilitated significant speed up of laboratory tests and reduce of their cost.

Cross-correlation-based convolutional neural network with velocity regularization for high-resolution velocimetry of particle images

Particle image velocimetry (PIV) stands as a pivotal experimental technique in fluid dynamics, enabling the visualization and analysis of fluid flows. Traditional methods for extracting velocity fields from particle images often rely on window-cross correlation PIV or, more recently, optical flow techniques rooted in intensity conservation principles. However, the former approach suffers from low resolution, whereas the latter is hampered by computational inefficiency and a high susceptibility to noise. Recent studies have demonstrated the effectiveness of convolutional neural networks (CNNs) in processing particle images to obtain high-resolution and high-accuracy velocity fields, though traditional CNN architectures are still not satisfying in accuracy. The present study introduces an enhanced network, En-FlowNetC, based on the cross correlation-based CNN FlowNetC, specifically designed to process PIV particle images and achieve high-accuracy, high-resolution velocity fields. It incorporates a velocity regularization and is trained and validated on canonical datasets. The results indicate that En-FlowNetC surpasses traditional CNN networks in accuracy and markedly outperforms the classic Horn–Schunck optical flow method in both complex and simple flow scenarios. Furthermore, this study confirms the beneficial impact of velocity regularization, when judiciously applied, on network accuracy. The proposed modifications compared to the original FlowNetC are also examined in the ablation experiments. Overall, En-FlowNetC provides an effective deep-learning solution for PIV analysis, paving the way for future endeavors aimed at achieving highly accurate and resolved velocimetry.

From Streamline to Pathline: Visualizing Particle Trajectories Under Changing Velocity Fields

Summary Monitoring of subsurface fluid motion is critical for optimizing hydrocarbon production and CO2 sequestration. Streamlines are frequently used to visualize fluid flow; however, they provide only an instantaneous snapshot of the velocity field and do not offer an exact representation of fluid movement under varying field conditions. In contrast, pathlines are constructed by tracking individual particles within the fluid, enabling us to trace the movement of these particles as they traverse through changing velocity fields. Pathline is the trajectory that an individual fluid particle follows in the reservoir. It can be thought of as “recording” the path of a fluid element in the flow field for a given time interval. Pathlines are distinct from streamlines which represent a snapshot of the velocity field at a given instant. The direction the path takes is determined by the streamlines at a specific instant. To start with, streamlines are traced based on the grid face fluxes of finite-difference simulation. Streamline tracing continues till the time of flight equals the current time. The endpoints of the current streamlines become the starting points for the next tracing period. Thus, our formulation incorporates changing flow fields, and the process is repeated for each time interval until the end. The proposed injection monitoring method is tested using a 3D field-scale model with complex geologic features to demonstrate its power and utility. The pathlines were compared with streamlines, as well as the water saturation distribution. Three scenarios are tested: a constant well schedule, a changing well schedule with partial shut-in, and a changing well schedule with a whole field cessation. Results indicate that the pathline provides a more accurate swept volume, consistent with saturation distribution. The robustness of our algorithm and implementation is demonstrated with a complex embedded discrete fracture model (EDFM) to visualize flow patterns in discrete facture network. Pathlines display the fluid flow across fractures and are subsequently used to explore the sweep efficiency and the well connectivity.

THE EFFECT OF POLYMER GEL ON THE OIL AND WATER PERMEABILITY DAMAGE IN A MICROFLUIDIC DEVICE

Microfluidics, a rapidly advancing field, finds wide applications in various domains, including enhanced oil recovery. This study delineates the methodology for fabricating a microchip with channels having a width of 50 μm, designed to simulate and visualize fluid flow in porous media. The microfluidic device was constructed using NOA81, a UV-curable polymer. Upon curing, it forms a robust and transparent microchip structure suitable for precise fluid control and analysis in microfluidic applications. Flood experiments conducted on the microchip revealed that the introduction of a 0.5 wt% polymer gel into the model's channels resulted in a reduction of water permeability by a factor of 106 and 25 at the shock front and after injection pressure stabilized, respectively. In contrast, oil permeability was reduced by at least 40 times.

Numerical Analysis of Gurney Flap Impact on NACA 4415 Airfoil Aerodynamics Performance

Improving airfoil aerodynamic performance is an essential aspect of aerodynamic technology. The use of passive flow control is one way to enhance the aerodynamic performance of the airfoil. The influence of using gurney flaps as passive flow control was explored through the CFD approach employing the RANS control equations with the k-epsilon turbulence model. The airfoil model utilized in this investigation was the NACA 4415 operating at a Reynolds number of 1×106. This study explored three different variations of flap height, namely 0.5%, 1%, and 2% of chord length. The outcomes showed that adding gurney flaps showed quite positive results in increasing the lift and drag performance of NACA 4415. An airfoil with a 0.5%c height flap has an average percentage increase in Cl of 12%, followed by a height flap of 1%c, which is 23%, and a percentage Cl of 37% for a height flap of 2%c. Meanwhile, each variation in height flap affected the increase in Cd. A height flap of 0.5%c increased Cd with an average percentage of 2%, while a height flap of 1%c increased the percentage of Cd by 4% and 6% for a height flap of 2%c. Moreover, visualization of fluid flow with pressure and velocity contours given at AoA 12º to determine the effect on the increase in Cland Cd in NACA 4415.

DIY-PIV system for Poiseuille flow investigation in undergraduate fluid mechanics course

Fluid flow visualization techniques are becoming more widespread every year due to the availability of lasers, high-speed cameras, and the development of a large amount of image processing software. Nowadays, one of the most popular methods of flow optical visualization is particle image velocimetry (PIV). PIV is an innovative way to measure and analyze fluid characteristics, giving students a more in-depth understanding of how fluids move. This paper is focused on using low-cost components and free software to implement PIV for Poiseuille flow investigation in an undergraduate fluid mechanics course. The introduction discusses how PIV is being used as a complementary method in educational institutions, highlights the high cost of equipment to implement PIV, and gives examples of low-cost do-it-yourself (DIY)-PIV systems. The following sections present the theoretical background, descriptions of the DIY-PIV experimental setup, and plan of the investigation for the Poiseuille flow analysis. A brief overview of free image processing software for the PIV implementation is also provided. The last section presents the results of the Poiseuille flow study and analyzes the measurement quality using the created DIY-PIV system. The present experimental investigation covers topics and reinforces skills related to concepts: laminar flow, Poiseuille flow (velocity distribution, maximum and average velocity), Reynolds number, and measurement error.

ANALISIS CFD PADA SAYAP MINI GLIDER DENGAN PENAMPANG LOW REYNOLD NUMBER AIRFOIL DAN FOLDED FLAT PLATE AIRFOIL

The purpose of this research is to make a very small unmanned aircraft as a teaching aid in aerospace engineering workshops, because of its very small size, this type of unmanned aircraft is abbreviated as Micro Air Vehicle, this MAV is only operated at low Reynolds numbers. MAV development research for smaller sizes continues to be carried out such as the Micro Glider. In this study, the author uses the Computational Fluid Dynamic method and the software used ANSYS Fluent and compares the existing DATCOM data, the author simulates the 4 types of airfoils into a wing object. The results of this study can be seen that based on the average deviation diff value that has been obtained in a population to determine the error from the comparison of the reference airfoil lift coefficient and its FFP by comparing the two methods, namely the IISHI airfoil reference geometry is 6.22% while the FFP is is 11.25% and the SD 7037 airfoil reference geometry is 3.71% while the FFP is 2.11%. Then for the comparison of the maximum lift to drag ratio values, it is obtained that the airfoil reference geometry (SD 7037) has a value of = 9.96 while the airfoil reference geometry (IISHI) has a value of = 8.81. In the Folded Flat Plate airfoil geometry (SD 7037) it has a value of = 7.61 while the Folded Flat Plate airfoil (IISHI) has a value of = 7.37. Then for the visualization of fluid flow can be obtained, namely the results of visualization of fluid flow in several parts of the angle of view / plane of the wing geometry when the AoA is high, namely the root plane to the half wing plane. early, while the geometry of SD 7037 (airfoil reference) is not easy to occur early turbulence flow. Second, that in general the fluid flow pattern seen in the FFP airfoil geometry (FFP IISHI) has the most dominant turbulence flow pattern (very much/large) while the FFP airfoil geometry (FFP SD 7037) has very little/small turbulence flow pattern..

Image Processing and CFD Simulation Method Comparison in Determining and Visualizing Fluid Flow of a Marine UAV

Image Processing and CFD Simulation Method Comparison in Determining and Visualizing Fluid Flow of a Marine UAV

Numerical and experimental analysis of fluid flow and flow visualization at low Reynolds numbers in a dimple pattern plate heat exchanger

This research discusses single-phase fluid flow conditions at low Reynolds number (Re) in the heat exchanger with a dimple structure of the heat plate. Flow at 70 ≤ Re ≤ 469 was investigated with laboratory experiments and computational fluid dynamics. It was found that in such a channel, two flow regimes exist, i.e., dead and live regimes. The volumetric fraction of the deadly regime gets bigger with increasing Re. At Re ≥ 469, a fully developed turbulent flow was found in the channel. Numerical analysis was made with a laminar flow model and two turbulence models, Realizable k−ε with an enhanced wall treatment and k−ω SST. The Realizable k−ε turbulent model with an enhanced wall treatment predicts pressure drop and shape of the live and dead regime more consistent with the real conditions in the channel. At the lowest considered Re = 70, computational fluid dynamics solutions deviate from laboratory experiments by −10.3 %. As the Re increases, the difference increases and reaches −18.3 % at Re = 141. As Re continues to increase, the result decreases and stabilizes at −8.3 %.

Experimental study on flow boiling-based micro-channel configurations for the PEMFC cooling

Proton Exchange Membrane Fuel Cell (PEMFC) is one of the most promising energy conversion devices. Efficient thermal management is crucial for maintaining the PEMFC's efficiency and durability. However, cooling the PEMFC can be challenging due to the small temperature differences between the stack's operating temperature and the surrounding environment. In the present study, flow boiling is applied as a cooling technique for the PEMFC. A flow boiling experimental test bench with fluid flow visualization is built for PEMFC cooling. To relieve the negative effect of mal-distribution of working fluid in the micro-channels, the cooling configurations with orifice baffles are also tested. Flow boiling performance of HFE-7100 in the micro-channel-based cooling configuration for PEMFC is experimentally investigated. The flow boiling characteristics of HFE-7100 in the micro-channel are revealed, which is beneficial for the appropriate design of flow boiling-based cooling configuration for the PEMFC. Excellent temperature distribution uniformity of flow boiling-based cooling PEMFC is achieved and is further enhanced by adding orifice baffles.

Core analysis in a changing world – how technology is radically benefiting the methodology to acquire, the ability to visualize and the ultimate value of core data

Abstract Core analysts principally study the storage, flow and saturation properties of porous rocks and sediments. Some of the derived parameters are specific to hydrocarbon production but many have commonality with other subsurface disciplines such as hydrology and soil science. Traditional core analysis involves direct physical experimentation on core plugs to derive a range of parameters used as calibration for conventional well logs, and to predict hydrocarbon reserves and recovery. The mechanisms and processes for obtaining such data have evolved significantly during the last century, from the manual instruments of the mid-twentieth century to the accredited digital data collection and recording of the 1990s onwards. X-ray micro- and nano-scale computed tomography (CT) imaging led to the development of the digital rock physics subdiscipline in the early 2000s. This has subsequently allowed direct visualization of fluid flow at the pore scale, imaging the wetting phase and multiphase fluid mobility. Multiscale imaging workflows are being developed to overcome issues around heterogeneous rock and the limited field of view associated with the highest resolution X-ray CT images. Hybrid workflows, which combine digital rock physics with traditional core analysis, are becoming increasingly common to meet the challenges associated with some of the most difficult to constrain properties, such as relative permeability. At a larger scale, the recent development of multisensor core logging (MSCL) tools has allowed the cost-effective acquisition of essentially continuous high-resolution 1D, 2D and 3D datasets from both slabbed and unslabbed whole core. Often aided by artificial intelligence to manage and interpret these large physical and chemical datasets, both new and legacy core can be rapidly screened to allow representative subsampling for detailed laboratory experimentation. The context and data provided by the MSCL then allows effective upscaling of these time- and cost-intensive point-source measurements. In the last decade, extended reality (XR) has resulted in a step change in the ability to visualize and integrate core and core-derived information with other subsurface datasets. A very wide range of scales can be managed effectively, from micrometre- to centimetre-scale petrographical and core analysis data, to metre-scale well logs and up to kilometre-scale 3D and 4D seismic. These tools allow stakeholders to work and meet from any location in a common workspace, and efficiently scale and interrogate data in a virtual 3D environment. The various advances in core analysis and associated technologies during the early twenty-first century mean that the study of porous media to help enable the energy transition looks assured. During the coming decades, applications as diverse as carbon capture, utilization and storage (CCUS), hydrogen storage, geothermal energy generation, mining for critical minerals, palaeoclimate studies, radioactive waste management, and site surveys for windfarms will all continue to benefit from the data and understanding derived from core analysis.

Letter: Contactless Ultrasonic Cavitation for the Prevention of Shunt Obstruction in Hydrocephalus: A Proof-of-Concept Study.

To the Editor: We read with great interest the article by Gomez-Gonzalez et al1 regarding a proof of concept concerning contactless ultrasonic cavitation that “has the potential to be used routinely as a noninvasive, preventative cleaning procedure to reduce the likelihood of obstruction-related events in patients with hydrocephalus treated with an implanted shunt.” The authors presented an elegant and novel approach to treatment of shunt obstruction, an all too common issue with which neurosurgeons must deal. Frustratingly, the neurosurgical community has moved forward with many technological improvements, while making limited progress in our biological management of hydrocephalus. Those of us who commonly treat patients with shunts know the failure rate is higher than we would like. However, in many cases, we have no better options. Neurosurgery has historically tried many minimally invasive techniques to reduce the morbidity of shunt revision. As the authors pointed out, there was a flurry of interest in these techniques because endoscopes became small enough to fit down the ventricular catheter and still allow good visualization. When the percutaneous endoscopic recanalization of the catheter (PERC) procedure was first published, there was international interest in the technique.2 We are not aware of any teams using similar techniques on a regular basis anymore. Personal experience with the PERC technique (Dr Trumble was second author on the article) confirmed it was a safe method for proximal shunt revision. However, the location of the obstruction was not consistently at the distal end (along the intraventricular holes) but sometimes along the lumen of the intracranial portion of the catheter. Endoscopic visualization allowed confirmation of location of obstruction, removal, and visualization of cerebrospinal fluid flow after recanalization. Placement of the instrumentation through the Rickham reservoir also allowed manometric confirmation of resumption of cerebrospinal fluid flow after the PERC procedure. We commend Gomez-Gonzalez et al for their novel approach to a common neurosurgical issue and look forward to clinical application of future techniques to improve the treatment of patients with hydrocephalus.

Design, Fabrication, and Experimental Validation of Microfluidic Devices for the Investigation of Pore-Scale Phenomena in Underground Gas Storage Systems

The understanding of multiphase flow phenomena occurring in porous media at the pore scale is fundamental in a significant number of fields, from life science to geo and environmental engineering. However, because of the optical opacity and the geometrical complexity of natural porous media, detailed visual characterization is not possible or is limited and requires powerful and expensive imaging techniques. As a consequence, the understanding of micro-scale behavior is based on the interpretation of macro-scale parameters and indirect measurements. Microfluidic devices are transparent and synthetic tools that reproduce the porous network on a 2D plane, enabling the direct visualization of the fluid dynamics. Moreover, microfluidic patterns (also called micromodels) can be specifically designed according to research interests by tuning their geometrical features and surface properties. In this work we design, fabricate and test two different micromodels for the visualization and analysis of the gas-brine fluid flow, occurring during gas injection and withdrawal in underground storage systems. In particular, we compare two different designs: a regular grid and a real rock-like pattern reconstructed from a thin section of a sample of Hostun rock. We characterize the two media in terms of porosity, tortuosity and pore size distribution using the A* algorithm and CFD simulation. We fabricate PDMS-glass devices via soft lithography, and we perform preliminary air-water displacement tests at different capillary numbers to observe the impact of the design on the fluid dynamics. This preliminary work serves as a validation of design and fabrication procedures and opens the way to further investigations.

Aerodynamics Improvement of NACA 0015 by Using Co-Flow Jet

This study analyzes co-flow as active flow control in the object of the airfoil. NACA 0015 is the airfoil used in this study. The airfoil was then modified to add co-flow jet features. Co-flow jet was placed on the upper chamber to analyze its effect on airfoil performance. Further, the Co-flow jet was studied by varying the injected mass flow rate ( ) in the injection slot. The variation of is 0.15, 0.20, and 0.25 kg/s. The study used CFD with the governing equation RANS. Reynolds Averaged Navier Stokes combined with turbulence model to solve all equations. Two equations for the turbulence model are used in this study. Specifically, this study discusses the aerodynamics of the airfoil, i.e., lift force, drag force, and fluid flow visualization, such as pressure contour and velocity contour. Co-flow jets can improve the aerodynamics of airfoils. The bigger the injected, the higher the lift coefficient increases. On the other hand, the drag force will be reduced as the number of injected fluid flow increases. Because of that, the airfoil efficiency will be better if using a co-flow jet. However, the C l / C d curve peak shifts to smaller as the injection fluid flow are bigger. The fluid flow visualization by velocity contour on AoA=20° revealed that the co-flow jet could overcome separation.

Nusselt number and friction characteristics of solar air heater roughened with novel twisted V-shaped staggered ribs using liquid crystal thermography

The objective of this study is to investigate the Nusselt number and friction characteristics of rectangular channel solar air heater (SAH) ducts roughened with staggered V-shaped ribs using the liquid crystal thermography technique. Experimentation is performed for Reynolds numbers ranges from 3000 to 21000, relative roughness pitch (P/e) of 7–11, relative roughness length (S/e) of 6.15–10.26, relative staggered distance (d/e) between 2 and 6, and fixed angle of attack (α) and relative twist length (y/e). The change in temperature of the roughened absorber surface that produced the RGB (red, green, blue) colour pattern is acquired by a charge-coupled device and converted into (Hue, Saturation, and Intensity) HSI using MATLAB. For all the varied parameters, results are discussed in terms of Nusselt number, friction factor, thermal enhancement factor, and visualization of fluid flows. Results show that the maximum augmentation ratio in Nusselt number and friction factor is 3.43 and 2.57 times more than that of a smooth duct, respectively. Among the varied roughness parameter, a maximum TEP value of 2.69 is noticed with P/e of 9, d/e of 4, and S/e of 6.15. It is concluded that inclusion of staggered twisted V-shaped ribs helps in enhancing heat transfer with the least amount of friction penalty.

Interactive Scientific Visualization of Fluid Flow Simulation Data Using AR Technology-Open-Source Library OpenVisFlow

Computational fluid dynamics (CFD) are being used more and more in the industry to understand and optimize processes such as fluid flows. At the same time, tools such as augmented reality (AR) are becoming increasingly important with the realization of Industry 5.0 to make data and processes more tangible. Placing the two together paves the way for a new method of active learning and also for an interesting and engaging way of presenting industry processes. It also enables students to reinforce their understanding of the fundamental concepts of fluid dynamics in an interactive way. However, this is not really being utilized yet. For this reason, in this paper, we aim to combine these two powerful tools. Furthermore, we present the framework of a modular open-source library for scientific visualization of fluid flow “OpenVisFlow” which simplifies the creation of such applications and enables seamless visualization without other software by allowing users to integrate the visualization step into the simulation code. Using this framework and the open-source extension AR-Core, we show how a new markerless visualization tool can be implemented.

Fabrications and Applications of Micro/Nanofluidics in Oil and Gas Recovery: A Comprehensive Review

Understanding fluid flow characteristics in porous medium, which determines the development of oil and gas oilfields, has been a significant research subject for decades. Although using core samples is still essential, micro/nanofluidics have been attracting increasing attention in oil recovery fields since it offers direct visualization and quantification of fluid flow at the pore level. This work provides the latest techniques and development history of micro/nanofluidics in oil and gas recovery by summarizing and discussing the fabrication methods, materials and corresponding applications. Compared with other reviews of micro/nanofluidics, this comprehensive review is in the perspective of solving specific issues in oil and gas industry, including fluid characterization, multiphase fluid flow, enhanced oil recovery mechanisms, and fluid flow in nano-scale porous media of unconventional reservoirs, by covering most of the representative visible studies using micro/nanomodels. Finally, we present the challenges of applying micro/nanomodels and future research directions based on the work.

Slip and temperature jump effects of MHD stagnation point flow towards a translating plate considering nonlinear radiations

AbstractThis article investigates the combined effects of nonlinear radiation and magnetic parameter under the velocity slip and temperature jump conditions on the boundary layer flow, arising in magnetohydrodynamics stagnation point flow toward a horizontal moving plate with constant velocity, . The governing mass, momentum, and energy equations are reduced into nonlinear ordinary differential equations with boundary conditions using the relevant similarity variables. The reduced boundary value problem is regulated by the magnetic parameter, slip parameter, temperature jump parameter, Prandtl number, radiation parameter, and temperature ratio parameter. In the absence of an analytic solution, the reduced equations are then demonstrated numerically using the shooting technique. The effects of parameters on the flow domain are analyzed using tables and figures. Moreover, two‐dimensional streamlines are plotted for visualizing fluid flow. It is found that the temperature decreases as the magnetic parameter, slip parameter, temperature jump parameter, and Prandtl number increase, but the opposite scenario is observed when the radiation parameter and temperature ratio parameter increase.

Visualization of non-Newtonian convective fluid flow with internal heat transfer across a rotating stretchable surface impact of chemical reaction

The present investigation focuses on the characteristics of heat and mass transfer in the context of their applications. There has been a lot of interest in the use of non-Newtonian fluids in engineering and biological disciplines. Having such considerable attention to non-Newtonian fluids, the goal is to explore the flow of Jeffrey non-Newtonian convective fluid driven by a non-linear stretching surface considering the effect of nonlinear chemical reaction effect. The relevant set of difference equations was changed to ordinary equations by using a transformation matrix. To create numerical solutions for velocity and concentration fields, the Runge–Kutta fourth-order method along with the shooting approach is utilized. The innovative fragment of the present study is to scrutinize the magnetized viscous non-Newtonian fluid over extending sheet with internal heat transfer regarding the inspiration of nonlinear chemical reaction effect, which still not has been elaborated on in the available works to date. Consequently, in the restrictive sense, the existing work is associated with available work and originated in exceptional agreement. Graphs depict the effects of various variables on motion and concentration fields, like the Hartman number, Schmidt number, and chemical reaction parameter. The performance of chemical reaction factor, Schmidt number, Hartmann number, and Deborah numbers on velocities component, temperature, and concentration profiles are discussed through graphs. The effect of emerging parameters in the mass transfer is also investigated numerically and 3D configuration is also provided. It is observed that the Deborah numbers and Hartmann numbers have the same effect on velocity components. Also, the thickness of the boundary layer reduces as the Hartmann number increases. As the Schmit number grows, the concentration field decline. For destructive and generative chemical reactions, the concentration fields observed opposite effects. It is also noticed that the surface mas transfer reduces as the Hartmann number rises. The statistical findings of the heat-transfer rate are also documented and scrutinized.

Effect of Single Slat and Double Slat on Aerodynamic Performance of NACA 4415

This study uses a Computational Fluid Dynamics (CFD) approach. The main object in this study is NACA 4415 with slat variations. The airfoil used as the slat is Eppler 421. Reynolds number in this study is 3 Í 10 6 . This study uses an unstructured mesh with a triangular cell shape with 137824 elements. The use of slats can improve the aerodynamic performance of NACA 4415. NACA 4415 without slat stalled at AoA=16º. Stall on airfoils with a single slat and double slat occurred at AoA=20º. Slat can increase C l in NACA 4415; however, the difference in C l increase is not much different when using a single slat or double slat. An airfoil with a single slat, on average, can increase C l by 20.9129%. The average increase in C l for an airfoil with a double slat is 25 . 6878%. Single slat and double slat increase C d . A single slat increased C d with an average increase of 26 . 1109%, and the average increase in C d for airfoils with double slat was 54 . 6152%. Single slat can produce a better C l to C d ratio than double slat, but the optimum AoA of double slat is 1º higher than single slat. Visualization of fluid flow at AoA=16° shows the fluid flow separation in the airfoil without a slat. The fluid flow separation can be handled well when NACA 4415 is given a single slat or double slat .