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Comments to K.M. Pervaiz Fathima, Ren\'e de Borst, Implications of single or multiple pressure degrees of freedom at fracture in fluid saturated porous media, Engineering Fracture Mechanics, 213 (2019), 1-20.

An overview of previous researches related to the problem of flow around a bluff-body, using experimental and numerical methods, is presented in the paper. Experimental investigation was performed by a laser doppler anemometer, measuring velocity components of the water flow around a smooth sphere, and a sphere with dimples in square channels. Measurement results in subcritical velocity flow field, velocity fluctuation components, lift, drag and pressure coefficients, and 2-D Reynolds stress at quasi-stationary flow are conducted using 1-D laser doppler anemometer probe. The obtained experimental results are compared with numerical simulations, which are performed using the ANSYS-CFX software. For the numerical simulations of quasi-steady-state flow, k-? turbulent model was used, while for numerical simulation of unsteady fluid-flow and for the comparison of results related to the eddy structures, vortex shedding and Reynolds stresses, detached eddy simulation were used. Since the obtained results of experimental and numerical investigation of flow around smooth sphere and sphere with dimples showed good agreement, the considered flow problem was expanded by introducing the influence of a transverse magnetic field with a slight modification of the electrical conductivity of the working fluid. The other physical properties of the fluid remained the same, which also corresponds to realistically possible physical conditions. Numerical simulations were performed for three different values of Hartmann number and very small values of Reynolds magnetic number (inductionless approximation). Comparisons and analyzes of the results were made for the cases containing a magnetic field and those with an absence of a magnetic field.

Heterogeneous fracture aperture distribution, dictated by surface roughness, mechanical rock and fracture properties, and effective stress, limits the predictive capabilities of many reservoir‐scale models that commonly assume smooth fracture walls. Numerous experimental studies have probed key hydromechanical responses in single fractures; however, many are constrained by difficulties associated with sample preparation and quantitative roughness characterisation. Here, we systematically examine the effect of roughness on fluid flow properties by 3D printing seven self‐affine fractures, each with controlled roughness distributions akin to those observed in nature. Photogrammetric microscopy was employed to validate the 3D topology of each printed fracture surface, enabling quantification using traditional roughness metrics, namely the Joint Roughness Coefficient (JRC). Core‐flooding experiments performed on each fracture across eight incremental confining pressure increases (11 to 25 bar), shows smoother fractures (JRC < 5.5) exhibit minor permeability variation, whilst rougher fractures (JRC > 7) show as much as a 219% permeability increase. Micro‐computed tomography imaging of the roughest fracture under varying effective stresses (5 to 13.8 bar), coupled with inspection into the degree of similarity between fracture closure behaviour in 3D‐printed and natural rock fractures, highlight the capabilities of 3D‐printed materials to act as useful analogues to natural rocks. Comparison of experimental data to existing empirical aperture‐permeability models demonstrates that fracture contact area is a better permeability predictor than roughness when the mechanical aperture is below ∼20 μm. Such findings are relevant for models incorporating the effects of heterogeneous aperture structures and applied stress to predict fracture flow in the deep subsurface.

Geological modelling is widely used to predict resource potential in subsurface reservoirs. However, modelling is often slow, requires use of mathematical methods that are unfamiliar to many geoscientists, and is implemented in expert software. We demonstrate here an alternative approach using sketch-based interface and modelling, which allows rapid creation of complex three-dimensional (3D) models from 2D sketches. Sketches, either on vertical cross-sections or in map-view, are converted to 3D surfaces that outline geological interpretations. We propose a suite of geological operators that handle interactions between the surfaces to form a geologically realistic 3D model. These operators deliver the flexibility to sketch a geological model in any order and provide an intuitive framework for geoscientists to rapidly create 3D models. Two case studies are presented, demonstrating scenarios in which different approaches to model sketching are used depending on the geological setting and available data. These case studies show the strengths of sketching with geological operators. Sketched 3D models can be queried visually or quantitatively to provide insights into heterogeneity distribution, facies connectivity or dynamic model behaviour; this information cannot be obtained by sketching in 2D or on paper. Supplementary material: Rapid Reservoir Modelling prototype (executable and source code) is available at: https://bitbucket.org/rapidreservoirmodelling/rrm. Supplementary screen recordings for the different case studies showing sketch-based modelling in action are available at https://doi.org/10.6084/m9.figshare.c.5084141 and supplementary figure S1-S4 are available at https://doi.org/10.6084/m9.figshare.c.5303043

Heat transfer in a partially-filled, rotating inclined pipe with water flowing through it is experimentally investigated. The test section is a 1000 mm long stainless steel pipe with 32.8 mm inner diameter and 1.1 mm wall thickness. The outer wall is painted black to improve its emissivity. The outer wall temperature distribution is captured using a thermal camera. Uniform wall heat flux (1405-10784 W/m(2)), water volumetric flow rate (100-830 ml/min), rotation rate (10-300 RPM) and pipe inclination angle (3 degrees and 6 degrees) are varied to study their influence on the heat transfer coefficient. Local heat transfer coefficient along the length of the partially filled rotating test section is reported. While heat transfer coefficient increases with the increase in wall heat flux, liquid volume flow rate and rotation rate, it decreases with increase in inclination angle. A generalised correlation to predict the average Nusselt number is developed in terms of four dimensionless numbers, viz., the flow Reynolds number to capture the effect of the axial fluid flow, rotation Reynolds number to account for the effect of pipe rotation, flow Froude number to take care of the effect of pipe inclination and dimensionless heat flux to incorporate the effect of wall heat flux on the heat transfer coefficient. (C)2018 Elsevier Ltd. All rights reserved.

WOS: 000454670400024, In the present work, the effect of the dfferent geometric moist objects with straight and reverse semi-circular on the heat and mass transfer enhancement of the jet drying was conducted with a numerical analysis. The drying jet was a laminar 2-D jet stationed at a constant jet distance from the moist object. The diameter of the object, jet distance from the moist object and initial jet height were fixed in all cases. Temperature and mass distributions were obtained inside the object for dfferent jet velocities. A finite volume method was used to solve the governing equations for momentum and energy by using ANSYS Fluent 17.0 software program. Calculations were performed for four dfferent Reynolds numbers, namely, Re = 100, 200, 300, and 400. It was found good agreement with the experimental data available in the literature. The results showed that the geometry of straight semi-circular moist object had better performance of heat and mass transfer than that of the reverse moist object geometry. In addition, increasing Reynolds number showed a positive effect on heat and mass transfer. Locally, jet drying was found to be most effective near the stagnation point on the leading side of the objects.

International audience; In this paper, an enthalpic lattice Boltzmann method formulation for 3D unsteady convection-diffusion heat transfer problems is used to overcome discontinuity issues in heterogeneous media. The new formulation is based on the appearance of a source term added to the collision step. The major achievement of the proposed enthalpic LB formulation is avoiding any interface treatments or geometry considerations even when dealing with complex geometries. The performance of the present method is tested for several three-dimensional convection-diffusion problems. Comparisons are made with the control volume method, and numerical results show excellent agreements.

A fully coupled three-dimensional finite-element model for hydraulic fractures in permeable rocks is presented, and used to investigate the ranges of applicability of the classical analytical solutions that are known to be valid in limiting cases. This model simultaneously accounts for fluid flow within the fracture and rock matrix, poroelastic deformation, propagation of the fractures, and fluid leakage into the rock formation. The model is validated against available asymptotic analytical solutions for penny-shaped fractures, in the viscosity-dominated, toughness-dominated, storage-dominated, and leakoff-dominated regimes. However, for intermediate regimes, these analytical solutions cannot be used to predict the key hydraulic fracturing variables, i.e. injection pressure, fracture aperture, and length. For leakoff-dominated cases in permeable rocks, the asymptotic solutions fail to accurately predict the lower-bound for fracture radius and apertures, and the upper-bound for fracture pressure. This is due to the poroelastic effects in the dilated rock matrix, as well as due to the multi-dimensional flow within matrix, which in many simulation codes is idealised as being one-dimensional, normal to the fracture plane.

Most carbonates have a dual porosity and permeability (matrix and fracture). As fractures are preferential conduits for fluid flows, fracture networks strongly impact reservoir hydraulic properties. Two fracture patterns can affect reservoirs: random background fractures in the host rock; and damage-zone-clustered fractures in fault zones. This study identifies the structural and diagenetic attributes of both fracture patterns and determined their respective impact on reservoir properties. The study focuses on the eastern part of La Fare Anticlinal (SE France). Lower Cretaceous, Urgonian facies carbonates underwent a polyphase tectonic history. Faults were set up as normal and were later reactivated as strike-slip. We made a 290 m scanline along the outcrop to characterize the fracture network in and outside the fault zones. The diagenetic analysis of 45 thin sections in polarized light microscopy with scanning electron microscopy and cathodoluminescence evidenced three cementation phases and two micrite recrystallization phases. This study shows that fault-zone structural properties and deformation are dependent of the initial host-rock background fracture network. The fault-zone structure with a damage-zone fracture network encouraged fluid flow and the cementation of S2 phase. This fluid flow, absent in the host rock, strongly modified the reservoir properties of the studied zone. Thematic collection: This article is part of the Naturally Fractured Reservoirs collection available at: https://www.lyellcollection.org/cc/naturally-fractured-reservoirs

Large-Eddy Simulation of heat transfer in plate and pin fin heat exchangers is carried out under constant surface temperature assumption while resolving the surface heat flux by a dense mesh of 28 M cells. The heat exchangers are mounted inside a pipe in a highly constrained space. The heat transfer takes place by forced convection at Re D = 20000 . The numerical simulations are validated by comparison of velocity profiles against experimental flow measurements on 3D-printed aluminium heat exchangers. Both the experiments and simulations indicate higher rate of heat transfer on the outer fins. The numerical findings indicate that, for the plate heat exchanger, the average Nusselt number of the outermost fins is approximately 50 % larger than at the inner fins ( Nu = 7.54 ). For the pin fin heat exchanger, we observe a 20 % increase in the Nusselt number between the inner and the outer fins. A strongly localized vortex shedding region is observed for the pin fin heat exchanger increasing the local heat transfer by a factor of two. In contrast, for the planar fins, the flow appears steady and laminar in the interior. In addition to strong flow diversion observed for both geometries, we show that for the pin fin array, almost 50 % of the flow that enters the heat exchanger leaks to the clearances through the side and tip gaps. For the planar fins, the respective leakage is only 30 % . Numerical evidence is also provided on the relevance of variety of flow phenomena including recirculation zones, vortex shedding, flow laminarization as well as flow separation and reattachment, all affecting the local heat transfer.

Tidal heterolithic sandstone reservoirs are heterogeneous at the submeter scale because of the ubiquitous presence of intercalated sandstone and mudstone laminae. Core-plug permeability measurements fail to sample a representative volume of this heterogeneity. Here, we investigate the impact of mudstone drape distribution on the effective permeability of heterolithic, cross-bedded tidal sandstones using three-dimensional, surface-based “minimodels” that capture the geometry of cross beds at an appropriate scale. The impact of seven geometric parameters has been determined: (1) mudstone fraction, (2) sandstone laminae thickness, (3) mudstone drape continuity, (4) toeset dip, (5) climb angle of foreset–toeset surfaces, (6) proportion of foresets to toesets, and (7) trough or tabular geometry of the cross beds. We begin by identifying a representative elementary volume of 1 m3 (∼35 ft3), confirming that the model volume of 9 m3 (∼318 ft3) yields representative permeability values. Effective permeability decreases as the mudstone fraction increases, and it is highly anisotropic: vertical permeability falls to approximately 0.5% of the sandstone permeability at a mudstone fraction of 25%, whereas the horizontal permeability falls to approximately 5% and approximately 50% of the sandstone value in the dip (across mudstone drapes) and strike (parallel to mudstone drapes) directions, respectively. Considerable spread exists around these values, because each parameter investigated can significantly impact effective permeability, with the impact depending upon the flow direction and mudstone fraction. The results yield improved estimates of effective permeability in heterolithic, cross-bedded sandstones, which can be used to populate reservoir-scale model grid blocks using estimates of mudstone fraction and geometrical parameters obtained from core and outcrop-analog data.

Building geometrically realistic representations of geological heterogeneity in reservoir models is a challenging task that is limited by the inflexibility of pre-defined pillar or cornerpoint grids. The surface-based modelling workflow uses grid-free surfaces that allows efficient creation of geological models without the limitations of pre-defined grids. Surface-based reservoir modelling uses a boundary representation approach in which all heterogeneity of interest (structural, stratigraphic, sedimentological, diagenetic) is modelled by its bounding surfaces, independent of any grid. Volumes bounded by these surfaces are internally homogeneous and, thus, no additional facies or petrophysical modelling is performed within these geological domains and no grid or mesh discretisation is needed during modelling. Any heterogeneity to be modelled within such volumes is incorporated by adding surfaces. Surfaces and curves are modelled using a parametric non-uniform rational B-splines (NURBS) description. These surfaces are efficient to generate and manipulate, and allow fast creation of multiple realisations of geometrically realistic reservoir models. Multiple levels of surface hierarchy are introduced to allow modelling of all features of interest at the required level of detail; surfaces at one hierarchical level are constructed so as to truncate or conform to surfaces of a higher hierarchical level. This procedure requires the joining, terminating and stacking of surfaces to ensure that models contain “watertight” surface-bounded volumes. NURBS curves are used to represent well trajectories accurately, including multi-laterals or side-tracks. Once all surfaces and wells have been generated, they are combined into a reservoir model that takes into account geological relationships between surfaces and preserves realistic geometries.

This study presents the stochastic Monte Carlo simulation (MCS) to assess the uncertainty of flow and conservative transport in 3-D discrete fracture networks (DFNs). The MCS modeling workflow involves a number of developed modules, including a DFN generator, a DFN mesh generator, and a finite element model for solving steady-state flow and conservative transport in 3-D DFN realizations. The verification of the transport model relies on the comparison of transport solutions obtained from HYDROGEOCHEM model and an analytical model. Based on 500 DFN realizations in the MCS, the study assesses the effects of fracture intensities on the variation of equivalent hydraulic conductivity and the exhibited behaviors of concentration breakthrough curves (BTCs) in fractured networks. Results of the MCS show high variations in head and Darcy velocity near the specified head boundaries. There is no clear stationary region obtained for the head variance. However, the transition zones of nonstationarity for x-direction Darcy velocity is obvious, and the length of the transition zone is found to be close to the value of the mean fracture diameter for the DFN realizations. The MCS for DFN transport indicates that a small sampling volume in DFNs can lead to relatively high values of mean BTCs and BTC variations.

We present a path integral formulation of Darcy's equation in one dimension with random permeability described by a correlated multi-variate lognormal distribution. This path integral is evaluated with the Markov chain Monte Carlo method to obtain pressure distributions, which are shown to agree with the solutions of the corresponding stochastic differential equation for Dirichlet and Neumann boundary conditions. The extension of our approach to flow through random media in two and three dimensions is discussed.

Single phase heat transfer in a partially-filled, rotating horizontal pipe with axial liquid (water) flow is studied in this work. Thermal imaging is used to capture outer wall temperature of the partially filled rotating heated pipe. Local heat transfer coefficient along the length of the rotating pipe is calculated. Various parameters influencing the heat transfer coefficient i.e. heat flux (779–12522 W/m2), flow rate (6–80 LPH) and rotation rate (5–300 RPM) are identified and reported. It is observed that heat transfer is positively influenced by heat flux, flow rate and rotation rate. A generalised correlation is developed based on dimensionless heat flux, flow and rotation Reynolds number to predict the average Nusselt numbers. This study is expected to provide insight into single phase heat transfer characteristics of a partially filled rotating heated pipe.

This paper presents an investigation of flow and heat transfer in a large diameter (6.25 in) cylindrical enclosure heated laterally and containing a porous block that simulates the basket of nutrients used in a crystal growth reactor. The numerical model entails the use of a commercially available computational engine provided by ANSYS FLUENT, and based on a two-dimensional (2D) axisymmetric Reynolds-averaged Navier Stokes (RANS) equations. The porous medium is simulated using the Brinkman-extended model accounting for the Darcy and Forchheimer induced pressure drops. The porous 'plug' effects are analyzed as both its permeability/inertial resistance and locations in the reactor are changed on a parametric basis, while the Rayleigh number (Ra = g beta Delta TL3/v alpha) is kept constant at 1.98 x 10(9). Additionally, the effect of different ratios of the hot to the cold zone lengths are investigated as a part of the current effort. For all cases, the velocity and temperature distributions in the reactor are analyzed together with the flow patterns in, and around the porous block. A comprehensive discussion is provided with regard to the effects of the position of the porous block and its permeability on both the immediately adjacent, and far flows. The consequences on the temperature distribution in the enclosure, when the ratio of the length of the hot-to-cold zones is changed, are also analyzed. (C) 2017 Elsevier B.V. All rights reserved.

Concentric tube heat exchangers are used extensively by the energy industry. In the present study, the behavior of overall heat transfer coefficient with randomized packing of uniformly sized spheres inside the concentric tube heat exchangers is investigated at the laboratory scale. In this work, the heat transfer coefficient on the tube side is calculated using the experimental measured hot and cold fluid temperature differences, mass flow rates of hot and cold fluid. The correlations of are used to calculate the convective heat transfer coefficient (ho) on the annular side and tube side of the concentric tubes packed with uniform sized spheres. However, the logarithmic mean temperature difference is the assumption made for the temperature difference across the packed bed. The calculated overall heat transfer coefficient using correlation and experimental measured one are in very good agreement for a given heat load. The reduction in length in comparison to heat exchangers without packing is found to be ∼95%. A packed bed heat exchanger design methodology is presented.

A microvalve-based bioprinting system for the manufacturing of high-resolution, multimaterial 3D-structures is reported. Applying a straightforward fluid-dynamics model, the shear stress at the nozzle site can precisely be controlled. Using this system, a broad study on how cell viability and proliferation potential are affected by different levels of shear stress is conducted. Complex, multimaterial 3D structures are printed with high resolution. This work pioneers the investigation of shear stress-induced cell damage in 3D bioprinting and might help to comprehend and improve the outcome of cell-printing studies in the future.

A simplified model for predicting the overall thermal performance of finned-tube heat exchangers considering water and air as hot and cold fluids, respectively, is investigated. The model is based on the classical epsilon-NTU method and the thermal convective resistance in each fluid is estimated after conventional type (Nusselt number) empirical correlations. The model is calibrated with catalogue data of a heating coil. Calibrations of six families of model versions are performed by using different numbers of operating cases ranging from 2 to 320, some of them taking into account the influence of varying properties. The calibrated versions are tested for operating cases listed in the catalogue and the best performing versions are identified, such as the one calibrated with 24 cases and taking into account the effect of the fluid properties, which provided better accuracy than the versions calibrated in previous works. A test of the method robustness is conducted regarding the influence of the initial guessed values of the thermal resistances on the calibration procedure. The validity of the component model is further investigated by using a set of published experimental data for an automotive radiator covering ranges of practical interest of the mass flow rates of both air and water streams, and some versions providing excellent results are identified. The model based on a suitable version previously calibrated and tested is a promising procedure for the modular component simulation of finned-tube heat exchangers, when used as air conditioning heating coils or in other particular applications. (C) 2016 Elsevier Ltd. All rights reserved.

In this paper, the characterization of laminar convective heat transfer in rhombic shaped microchannel with H1 (axially constant heat flux and circumferentially constant temperature) and H2 (constant axial and circumferential wall heat flux) boundary conditions is presented. A three-dimensional numerical model is developed for hydrodynamically and thermally developing flow in different rhombic geometries with side-angles varying from 10 degrees to 90 degrees. The numerical model is first validated with the other model developed in the literature for rectangular geometry and subsequently the results are compared with rhombic channel with different side-angles. This model is then extended to determine the temperature and heat flux distributions in rhombic microchannel, which is used to find the local and hydrodynamically and thermally fully developed Nusselt numbers. It is found that the fully developed Nusselt number varies only with the side-angles of rhombic channel and generalized correlations are developed as a function of side-angles for H1 and H2 boundary conditions. Correlations for developing length, local and fully-developed Nusselt numbers for rhombic channels are currently not available. These results will be useful in design and optimization of rhombic microchannel for electronic cooling applications. (C) 2016 Elsevier Masson SAS. All rights reserved.

Mountainous regions of India experience recurrent slope failures due to rapid urbanization. The main causes of slope failure are high precipitation aided by unplanned construction of cut slopes. Such slope failures are further aggravated because of the presence of low strength, highly jointed, stratified rocks rich in clay minerals. In general, effect of weathering is more pronounced in these rocks, which causes long-term time-dependent deterioration of the rocks as well as joint strength. In this regard, the present investigation deals with the causes, behavior, and mechanism of slope failure by examining a section in the North Eastern Himalayas. A detailed field investigation was carried out for examining the existing condition of slope, slope material, and joint parameters. Laboratory experiments like compressive and tensile strength tests along and across the lamination planes along with slake durability index tests were conducted to characterize the material and investigate the role of weathering in strength degradation. Later, numerical simulation was performed employing distinct element method to investigate the failure behavior, mechanism, and also the effect of water pressure in destabilizing the slope. The experimental result indicates directional strength variations parallel and perpendicular to bedding plane, which makes the rock incompetent to sustain external load. The presence of orthogonal joint sets accelerates the process of block detachment. Significant slaking was observed which further deteriorates and fragments the rock at deeper level. Numerical simulation shows that failure plane is dominantly planar (along the bedding parallel joints) and surficial.

The effect of pore-scale heterogeneity on non-Darcy flow behaviour is investigated by means of direct flow simulations on 3-D images of a beadpack, Bentheimer sandstone and Estaillades carbonate. The critical Reynolds number indicating the cessation of the creeping Darcy flow regime in Estaillades carbonate is two orders of magnitude smaller than in Bentheimer sandstone, and is three orders of magnitude smaller than in the beadpack. It is inferred from the examination of flow field features that the emergence of steady eddies in pore space of Estaillades at elevated fluid velocities accounts for the early transition away from the Darcy flow regime. The non-Darcy coefficient β, the onset of non-Darcy flow, and the Darcy permeability for all samples are obtained and compared to available experimental data demonstrating the predictive capability of our approach. X-ray imaging along with direct pore-scale simulation of flow provides a viable alternative to experiments and empirical correlations for predicting non-Darcy flow parameters such as the β factor, and the onset of non-Darcy flow.

The present work deals with the determination of transient variation of temperature distributions inside laser irradiated biological tissue phantoms consisting of an artery vein counter current arrangement. An optical inhomogeneity that is absorbing in nature and embedded inside an otherwise homogenous medium has been employed to model the abnormal cells. The surrounding tissue region has been modeled as a porous medium consisting of solid and fluid matrices. Separate energy equations for solid and fluid matrices of the porous tissue regions have been solved as part of the bio-heat transfer model. A short pulse laser has been employed to irradiate the phantom. A numerical model coupling the Discrete Ordinates Method (DOM) for solving the transient form of Radiative Transport Equation (RTE) with that of the porous media based bio-heat transfer model has been developed and benchmarked. The convective cooling effects of blood flow through a single blood vessel as well as counter current blood vessels under local thermal non-equilibrium (LTNE) conditions have been investigated. Thermal response of the porous tissue phantom with respect to the changes in the Reynolds number (Re =1 and 10) and for varying porosity levels has been presented. The effect of blood vessel diameter on the resultant temperature distribution within the body of the laser irradiated tissue phantom has been studied. Results have been presented in the form of temporal variations of temperature distributions, local variations in the heat transfer rates (Nusselt numbers) along the spatial dimensions of various interfaces present in the physical domain. Finally, the influence of the position of the embedded inhomogeneity with respect to the point of laser irradiation on the temperature rise at the location of the inhomogeneity has been investigated. The study reveals a strong dependence of the maximum possible temperature rise on the relative position of the embedded abnormal cells for a given set of laser parameters. (C) 2016 Elsevier Ltd. All rights reserved.

International audience; A desiccant wheel model has been developed in the aim to be adapted to building simulation tools. This model fulfils several criteria such as simplicity of parameterization, accuracy, possibility to characterize the equipment under all operation conditions and low computation time. The method of characteristics has been applied to the heat and mass transfer partial differential equations. This transformation provides new equations which are similar to those of a rotary heat exchanger. Then, the model is described by the Effectiveness-NTU method and it is identified from only one nominal rating point. The model has been compared to experimental and manufacturers' data for a broad range of operating conditions. A good agreement has been found.

The recent development of bone-on-chips (BOCs) holds the main advantage of requiring a low quantity of cells and material, compared to traditional In Vitro models. By incorporating hydrogels within BOCs, the culture system moved to a three dimensional culture environment for cells which is more representative of bone tissue matrix and function. The fundamental components of hydrogel-based BOCs, namely the cellular sources, the hydrogel and the culture chamber, have been tuned to mimic the hematopoietic niche in the bone aspirate marrow, cancer bone metastasis and osteo/chondrogenic differentiation. In this review, we examine the entire process of developing hydrogel-based BOCs to model In Vitro a patient specific situation. First, we provide bone biological understanding for BOCs design and then how hydrogel structural and mechanical properties can be tuned to meet those requirements. This is followed by a review on hydrogel-based BOCs, developed in the last 10 years, in terms of culture chamber design, hydrogel and cell source used. Finally, we provide guidelines for the definition of personalized pathological and physiological bone microenvironments. This review covers the information on bone, hydrogel and BOC that are required to develop personalized therapies for bone disease, by recreating clinically relevant scenarii in miniaturized devices.