Radial Flow Pattern Research Articles

Non-equilibrium solute transport in a fractured rock matrix system under a radial flow pattern

Non-equilibrium solute transport in a fractured rock matrix system under a radial flow pattern

Small island morphometry analysis with remote sensing and GIS methods on the Satonda volcanic island

DEMNAS and Sentinel-1 are profoundly utilized for the small island morphometry analysis. This study explores the Satonda Island-West Nusa Tenggara landforms through the morphometry analysis using the DEM application and GIS analysis. As a volcanic island the Satonda Island coverage area is approximately about 2.600hectare dominated by the slopes with the steep slope (16o – 35o) at the northwest in a moderately steep (8° – 16°) at the southeast. Here, we uncover that the Satonda Island experiences five landforms carved by volcanic processes and other five are generated by the marine processes. As a typical of volcanic island, this island has a cone shape with the caldera founded in the middle with the radial flow pattern.

Large variation in the radial patterns of sap flow among urban trees

Quantifying sap flow patterns along the sapwood radius is necessary for accurate up-scaling and estimation of tree and stand transpiration based on sap flow measurements. However, little information on radial patterns of sap flow exists in urban environments where precise estimates of tree water uptake and transpiration are important to quantify ecosystem services and plan tree management. Because of the heterogeneous conditions in urban environment, upscaling approaches specific to urban environments and species may be required to estimate whole-tree transpiration.We measured sap flow at four sapwood depths for Acer platanoides, Acer saccharinum and Tilia cordata, in two contrasting urban environments (site types): parks and streets, in Montreal, Canada. We then estimated the potential importance of tree-to-tree and temporal variation of radial patterns by comparing generalized additive models (GAM) with or without tree ID or a temporal effect, and using the models to upscale sap flow measurements conducted at the sapwood surface to tree-level daily water use estimates.The radial pattern of sap flow diverged between park and street trees, with a slightly more monotone pattern in park than street trees in the two Acer species. However, tree-to-tree variation was large even within a given species and site type, and partly associated with tree size. The radial pattern of sap flow varied in time in five of the twelve trees that were measured twice over the growing season. Sap flow in deeper layers relative to the sapwood surface correlated with vapor pressure deficit, solar radiation and the sap flow density at the sapwood surface. When comparing the two sources of uncertainty (tree-to-tree and temporal variation) in upscaling daily water use, a larger uncertainty was associated with tree-to-tree variation than with temporal variation. Thus, understanding the inter-tree variability in radial patterns of sap flow patterns should be prioritized in future studies.

A PIV study to quantify the relationships between viscoelasticity and flow behavior in stirred tanks

Quantitative data on fluid dynamics in stirred tanks with viscoelastic fluids are scarcely available. Therefore, a particle image velocimetry study on flow phenomena occurring when agitating viscoelastic liquids with radial and axial impellers is presented. Different flow regimes exist, which result from interactions between elastic normal stresses and inertial forces: While for all agitators an axial pumping effect is found in the elastic regime, (semi-)radial flow patterns result in inertia-dominated flows. In the transition regime, locally limited zones exist dominated by either elasticity or inertia. This leads to a flow compartmentalization, a related pseudo-stagnation flow and reduced circulation rates. Which of the flow regimes is present can be predicted by the use of the elasticity number. With it, circulation flow numbers and flow distributions are standardized: In elastic flow conditions, these are constant. Thus, a scaling of the log-normally distributed velocities to the tip speed in this regime is possible.

Heat transfer characteristics and novel optimization of a supercritical N-decane-Cooling tube under gravity condition

To study the flow and heat transfer characteristics of supercritical n-decane in the actual regenerative cooling tube, the heat transfer characteristics in a horizontal square tube under a single-side heated condition with considering and ignoring gravity were numerically investigated. The k-ωSST turbulence model was used and tested against the experimental data. The heat transfer characteristics on circumferential walls were presented and the radial flow pattern in the main flow zone and the boundary layer zone was analyzed to explore the mechanism of the heat transfer under gravity conditions. It was found that the heat transfer was enhanced at the bottom wall and weakened at the remaining three walls because of the secondary flow caused by gravity effect. Furthermore, the heat transfer would be enhanced when the velocity component of the boundary layer along the normal direction of the wall is toward the wall. Besides, a brand-new structure constructed by ribs section and smooth section was proposed. The additional pressure drop caused by the enhanced heat transfer structure can be reduced by up to 95.4% with the same heat transfer performance compared with the traditional ribs-tube structure which ribs spread all over a tube.

Microflows in two-generation alveolar cells at an acinar bifurcation.

The alveolus is a basic functional unit of the human respiratory system, and the airflow in the alveoli plays an important role in determining the transport and deposition of particulate matter, which is crucial for inhaled disease diagnosis and drug delivery. In the present study, taking advantage of the precise control ability of the microfluidic technique, a rhythmically expanding alveolar chip with multiple alveoli in two generations is designed and both the geometric and kinematic similarities are matched with the real human respiration system. With the help of a micro-PIV measurement system, the microflow patterns inside each alveolus can be studied. The observed vortex and radial flow patterns and the discovery of stagnant saddle points are similar to those captured in our previous platform with only one alveolus [Lv et al., Lab Chip 20, 2394-2402 (2020)]. However, the interactions between multiple alveoli also uncover new phenomena, such as the finding of stagnant saddle points in non-vortex flow patterns and significant differences in the flow pattern around the points between the time of T/4 and 3T/4. The obtained results could enrich the understanding of microflow in a whole alveolar tree with multiple generations.

Distributed encoding of curvilinear self-motion across spiral optic flow patterns

Self-motion along linear paths without eye movements creates optic flow that radiates from the direction of travel (heading). Optic flow-sensitive neurons in primate brain area MSTd have been linked to linear heading perception, but the neural basis of more general curvilinear self-motion perception is unknown. The optic flow in this case is more complex and depends on the gaze direction and curvature of the path. We investigated the extent to which signals decoded from a neural model of MSTd predict the observer’s curvilinear self-motion. Specifically, we considered the contributions of MSTd-like units that were tuned to radial, spiral, and concentric optic flow patterns in “spiral space”. Self-motion estimates decoded from units tuned to the full set of spiral space patterns were substantially more accurate and precise than those decoded from units tuned to radial expansion. Decoding only from units tuned to spiral subtypes closely approximated the performance of the full model. Only the full decoding model could account for human judgments when path curvature and gaze covaried in self-motion stimuli. The most predictive units exhibited bias in center-of-motion tuning toward the periphery, consistent with neurophysiology and prior modeling. Together, findings support a distributed encoding of curvilinear self-motion across spiral space.

Estimating curvilinear self-motion from optic flow with a biologically inspired neural system* *This work was supported by The Office of Naval Research ONR N00014-18-1-2283.

Optic flow provides rich information about world-relative self-motion and is used by many animals to guide movement. For example, self-motion along linear, straight paths without eye movements, generates optic flow that radiates from a singularity that specifies the direction of travel (heading). Many neural models of optic flow processing contain heading detectors that are tuned to the position of the singularity, the design of which is informed by brain area MSTd of primate visual cortex that has been linked to heading perception. Such biologically inspired models could be useful for efficient self-motion estimation in robots, but existing systems are tailored to the limited scenario of linear self-motion and neglect sensitivity to self-motion along more natural curvilinear paths. The observer in this case experiences more complex motion patterns, the appearance of which depends on the radius of the curved path (path curvature) and the direction of gaze. Indeed, MSTd neurons have been shown to exhibit tuning to optic flow patterns other than radial expansion, a property that is rarely captured in neural models. We investigated in a computational model whether a population of MSTd-like sensors tuned to radial, spiral, ground, and other optic flow patterns could support the accurate estimation of parameters describing both linear and curvilinear self-motion. We used deep learning to decode self-motion parameters from the signals produced by the diverse population of MSTd-like units. We demonstrate that this system is capable of accurately estimating curvilinear path curvature, clockwise/counterclockwise sign, and gaze direction relative to the path tangent in both synthetic and naturalistic videos of simulated self-motion. Estimates remained stable over time while rapidly adapting to dynamic changes in the observer’s curvilinear self-motion. Our results show that coupled biologically inspired and artificial neural network systems hold promise as a solution for robust vision-based self-motion estimation in robots.

Dry Season Transpiration and Soil Water Dynamics in the Central Amazon.

With current observations and future projections of more intense and frequent droughts in the tropics, understanding the impact that extensive dry periods may have on tree and ecosystem-level transpiration and concurrent carbon uptake has become increasingly important. Here, we investigate paired soil and tree water extraction dynamics in an old-growth upland forest in central Amazonia during the 2018 dry season. Tree water use was assessed via radial patterns of sap flow in eight dominant canopy trees, each a different species with a range in diameter, height, and wood density. Paired multi-sensor soil moisture probes used to quantify volumetric water content dynamics and soil water extraction within the upper 100 cm were installed adjacent to six of those trees. To link depth-specific water extraction patterns to root distribution, fine root biomass was assessed through the soil profile to 235 cm. To scale tree water use to the plot level (stand transpiration), basal area was measured for all trees within a 5 m radius around each soil moisture probe. The sensitivity of tree transpiration to reduced precipitation varied by tree, with some increasing and some decreasing in water use during the dry period. Tree-level water use scaled with sapwood area, from 11 to 190 L per day. Stand level water use, based on multiple plots encompassing sap flow and adjacent trees, varied from ∼1.7 to 3.3 mm per day, increasing linearly with plot basal area. Soil water extraction was dependent on root biomass, which was dense at the surface (i.e., 45% in the upper 5 cm) and declined dramatically with depth. As the dry season progressed and the upper soil dried, soil water extraction shifted to deeper levels and model projections suggest that much of the water used during the month-long dry-down could be extracted from the upper 2–3 m. Results indicate variation in rates of soil water extraction across the research area and, temporally, through the soil profile. These results provide key information on whole-tree contributions to transpiration by canopy trees as water availability changes. In addition, information on simultaneous stand level dynamics of soil water extraction that can inform mechanistic models that project tropical forest response to drought.

Modeling transient pressure behaviour of a multi-fractured horizontal well in a reservoir with an arbitrary boundary and different fracture networks by considering stress-sensitive effect

Combining horizontal drilling together with hydraulic fracturing greatly improves the economic viability of exploiting a tight reservoir, while the stress-sensitive effect raises the significant difficulty to accurately evaluate its well performance. In this paper, a semi-analytical model is proposed to evaluate transient pressure behaviour of a multi-fractured horizontal well (MFHW) in a naturally fractured reservoir with an arbitrary boundary and different fracture networks under stress-sensitive effect. More specifically, the boundary element method coupled with the Pedrosa's transform formulation is used to obtain accurate solutions of the nonlinear equations incorporated with stress-sensitive effect in an arbitrary-shaped reservoir with single-zone or two-zone matrix subsystems. Meanwhile, the Laplace-transform finite difference method can be utilized to semi-analytically deal with the nonlinear fracture subsystems consisting of primary, secondary, and natural fractures by dividing complex fracture networks into small fracture segments. The convergence-skin effect is then introduced to represent the radial flow pattern in hydraulic fractures near a horizontal wellbore. Not only can the effects of stress-sensitivity in the matrix and different fracture subsystems be respectively examined, but also the corresponding pressure responses together with pressure derivative curves are obtained. Such coupled theoretical formulations have been verified and then extended for field applications. The semi-analytical solution is found to be more accurate and reasonable than the solution with the uniform permeability modulus, while the stress-sensitivity has a dominant impact on the intermediate- and late-time flow periods. The convergence-skin effect can be aggravated in the late-time period by considering the inherent stress-sensitivity in a hydraulic fracture, especially at low fracture conductivity. Based on the sensitivity analysis associated with different networks, the initial fracture conductivity in primary and secondary fractures imposes a great impact on the early-stage bilinear flow and fluid feed regimes, while the initial fracture conductivity in natural fractures makes a difference to the transient pressure response in the transition flow regime. As the minimum fracture conductivity in the primary fractures decreases, such an influence becomes more dominant during the late-time flow period. However, the minimum fracture conductivity in secondary and natural fractures has an inappreciable effect on the flow regime. In the late-time flow period, the effect of boundary shape becomes more obvious on the type curves, especially for a relatively small reservoir compared with the size of a horizontal well intercepted by multiple hydraulic fractures. For a reservoir with two-zone systems, the smaller the mobility ratio in the two zones is, the earlier the boundary-dominated flow in the outer zone will commence. Not only does this study facilitate understanding the respective contribution of stress-sensitivity and convergence-skin effect on the well production, but also the newly proposed models can be applied to optimally design a hydraulic fracturing operation under various constraints.

CFD Analysis of Modified Rushton Turbine Impeller

Mixing units is one of the prime components in various chemical processing industries. The mixing equipment produces a product by combing different liquids at various properties. Generally, the mixing units are axial and radial flow types. The rushton turbine is one of the radial flow types and had higher power number due to fluid resistance as disadvantage. This works aims to investigate the four bladed rushton turbine impellers at eight angles for finding optimum power without compromising radial flow patterns. The shaft eccentricity hydrodynamics effect is also analysed on the unbaffled stirred vessels. The variance of eccentric and coaxial agitation is clearly evaluated on the several power number and impeller blade angle by experimental and numerical analysis. The CFD analysis is made on the mixing chamber to find the optimum inputs of the mixing chamber numerically by varying the blade angles.

Temperature impact on linear and radial wormhole propagation in limestone, dolomite, and mixed mineralogy

The temperature has a significant impact on acid stimulation efficiency in carbonate reservoirs. To fully understand its effect, this study utilizes a two-scale continuum model coupled with heat transfer. The study investigated the importance of the heat of reaction, injected acid temperature, and reservoir temperature on wormhole propagation and treatment efficiency. This research's novelty stems from its application to limestone, dolomite, and combined mineralogy in radial and linear flow patterns. It also investigated the role of vugs on acidizing efficiency in dolomite formations, showing that vugs improve wormhole penetration distance. The model reproduced the outcomes from the literature, showing that the heat of reaction has a negligible effect on wormhole propagation. On the contrary, increasing the injected acid temperature reduced the wormhole radius in limestone but improved its efficiency in dolomite. The acid could not create efficient wormholes at low acid temperatures in dolomite formation. It diverted itself towards the limestone in sequence mineralogy cases. Nevertheless, it equally stimulated the limestone and dolomite sections at elevated acid temperatures. The reservoir temperature was less critical than the acid temperature in determining the wormhole size and treatment efficiency. The model can be used to select the optimum temperature at which the most efficient wormhole is created.

A Novel Method to Gently Mix and Uniformly Suspend Particulates for Automated Assays.

The SpinVessel system provides a methodology using pulsed radial flow to gently mix and uniformly suspend particulates (cells, magnetic beads, silica beads, and microcarrier beads) for automated assays. SpinVessels are well suited for aliquoting on robotic liquid handlers and with robotic reagent dispensers, as well as manually. The SpinVessel system combines two critical features: (1) special internal side fins and projections in the bottom of the vessels and (2) an instrument that quickly spins the vessels and repeatedly reverses the spin direction. This rapid reversing motion sends multiple pulses of fluid up the side walls of the SpinVessel, creating a circular radial flow pattern. We tested five different particulates and six different SpinVessels with volume capacities varying from 50 mL to 1200 mL. SpinVessels are compatible with either single-, 8-, 12-, 96-, or 384-channel pipettors or with siphon tubing on robotic reagent dispensers. Experiments have demonstrated high viability of cells and undamaged morphology of microcarrier beads even after hours of constant agitation. The uniformity of aliquots collected at various vertical depths and horizontally across the SpinVessels demonstrated that cells, magnetic beads, and silica beads were uniformly suspended throughout the height and breadth of the SpinVessels, and uniformity of samples was consistent from the beginning to the end of the aliquoting procedure. Only 5 min of mixing is required to resuspend settled particulates. This novel mixing methodology has many applications in laboratory automation where particulate aliquot uniformity and/or particulate integrity are important to automating assays.

Geomorphology of the small island of Tidore and Hiri (North Maluku, Indonesia)

Tidore and Hiri Islands in North Maluku Province is the result of a complex tectonic setting. In contrast with Ternate Island and its well-known volcano, Gamalama volcano, there is still a lack of research about volcanic information or volcanic landform in Tidore and Hiri Islands. Even though the two islands also have volcanoes, i.e., Hiri and Tidore/Kiematubu volcano. This study aims to provide geomorphological information, especially in Tidore and Hiri Islands, since this information is hard to find whereas it is very important to disaster mitigation and landuse planning. We used remote sensing images, digital elevation models (DEM), and geological maps to classify geomorphological information of the small island of Tidore and Hiri in the North Maluku based on geomorphological aspects, i.e., morphology, morphogenesis, morpho-chronology, and morpho-arrangement. As a volcanic island, the slope in Tidore and Hiri Island is dominated by a slightly steep (8°-16°) and a steep slope (16°-35°), while the relief is dominated by hills and mountainous. Volcanic landforms on Tidore and Hiri Islands are characterized by relatively symmetrical cone-shaped volcanic cones, which are accumulations of falling pyroclastic material and lava ejected from magma vents. Volcanic islands include the case of Tidore and Hiri Island have radial centrifugal river flow patterns. The material on Tidore and Hiri Islands is dominated by Holocene volcanic rocks. In Tidore, there is alluvial material on the west and east coasts of the island. This study result also can be developed into more detailed geomorphological maps, or landscape evolution in a volcanic island, or spatial planning.

The screened waveguide for intrusive acoustic emission detection and its application in circulating fluidized bed

AbstractA screened waveguide with a 90° elbow, which had a rubber surface to reduce noise generations and a steel/air interface to block noise propagations, was designed to measure local particle movements in certain directions. In the riser of circulating fluidized bed, the noise energy only accounted for 2.1% of the total energy received by the waveguide. Besides, the radial acoustic emission energy distribution detected via the waveguide was highly consistent with the radial solid flux distribution measured by the extraction probe. Furthermore, the radial flow patterns in the riser with Geldart D particles were measured under dense phase conveying by this new method, which always demonstrated as core‐annulus flows and the transition points (r/R) increased with decreasing solid–gas ratios.

Roles of Barotropic Instability across the Moat in Inner Eyewall Decay and Outer Eyewall Intensification: Three-Dimensional Numerical Experiments

Abstract Radar imagery of some double-eyewall tropical cyclones shows that the inner eyewalls became elliptical prior to their dissipation during the eyewall replacement cycles, indicating that the barotropic instability (BI) across the moat (also known as type-2 BI) may play a role. To further examine the physics of inner eyewall decay and outer eyewall intensification under the influence of the type-2 instability, three-dimensional numerical experiments are performed. In the moist full-physics run, the simulated vortex exhibits the type-2 instability and the associated azimuthal wavenumber-2 radial flow pattern. The absolute angular momentum (AAM) budget calculation indicates, after the excitation of the type-2 instability, a significant intensification in the negative radial advection of AAM at the inner eyewall. It is further shown that the changes in radial AAM advection largely result from the eddy processes associated with the type-2 instability and contribute significantly to the inner eyewall decay. The budget calculation also suggests that the type-2 instability can accelerate the inner eyewall decay in concert with the boundary layer cutoff effect. Another dry no-physics idealized experiment is conducted and the result shows that the type-2 instability alone is able to weaken the inner eyewall and also strengthen the outer eyewall with nonnegligible effect.

Constraining late paleozoic ice extent in the Paganzo basin of western Argentina: Provenance of the lower Paganzo group strata

The western margin of Gondwana records evidence of mid-Carboniferous glaciation (Visean- Bashkirian) in the strata of the Paganzo Basin and adjacent areas. Previous studies focused on constraining the orientations of ice flow and generalizing the extent and occurrence of glacial ice in the basin. However, there is uncertainty occurs concerning the location and extent of glaciation and the locations of glacial centers during deposition of the Guandacol Formation located in the western portion and the time correlative Malanzán Formation in the eastern parts of the basin respectively. Understanding these strata and the conditions that led to the deposition of these strata has important implications for understanding glaciation extent along the western margin of Gondwana during the late Paleozoic ice age. To refine the glaciation history, we present new paleocurrent, facies, and a comparative analysis of previously published and one new detrital zircon geochronology data set. Together, these data provide new insight into sediment dispersal patterns and glacial centers within the basin. Our data indicate that both units were deposited under cold climatic conditions that occurred across the entire basin, but that glaciers were restricted to the western portion of the basin. The facies analysis for both formations indicates very different depositional environments for the two units: glacial and glaciomarine environments in the west and non-glacial alluvial, alluvial fan and lacustrine and/or marine environments in the east. Detrital zircon geochronology indicates separate localized provenance signatures for the two formations. Furthermore, the detrital zircon populations allude to disconnected depositional centers. At Huaco, glacial flow in the Guandacol is oriented toward the northwest (i.e. 313°) and appears to be draining from an uplift that contains similar zircon age populations as the Sierra de Valle Fértil and Sierra de Pie de Palo ranges. In the Olta-Malanzán paleovalley system, drainage was off valley walls and down the valley axis (i.e. south and southwest) within the Sierras de Chepes region with limited sediment sourced from the east just beyond the paleovalley system. Paleoflow measurements reported from other known glacial localities along the western portion of the basin reflect a radial flow pattern within and away from deeply incised valleys that clearly point to upland glacial centers within the Cuyania and Precordilleran terranes.

Static Water Level and Elevation Analyses of Shallow Hand-Dug Wells in Ilorin Metropolis, Nigeria

Aim: This study was conducted to reveal the depth to water level and surface elevation in selected hand-dug wells within Ilorin metropolis to assist in planning and management of water resources within the study area.
 Place and Duration of Study: The study was conducted in Ilorin metropolis, North Central, Nigeria.
 Methodology: A total of twenty-six (26) hand-dug wells were sampled and relevant spatial information was acquired using a handheld GPS; data collected include: longitude, latitude, elevation and depth to water, then the static water level above sea level was estimated by the difference between depth to water and elevation. Statistical analyses such as mean and standard deviation were determined, also a base map, contour maps and 3-D elevation model of the study area were produced using ArcGIS 10.4 and Surfer 10 software.
 Results: The depth to water within the study area ranges between 1.6 m and 13.3m, while elevation were between 284.1 m and 377.9 m, then the static water level ranges between 270.8 m and 371.4 m. The static water level contour map showed a radial and multidimensional groundwater flow pattern trending in the NE–SW and NW–SE directions while the 3-D elevation model revealed an undulating terrain.
 Conclusion: The study concluded that the depth to groundwater is relatively shallow and this can guide proper development and management of groundwater resources within the metropolis.

Pleistocene ignimbrites of western Armenia - Paleomagnetic and magnetic anisotropy constraints on flow direction and stratigraphy

Voluminous early to middle Pleistocene pyroclastic flow deposits were generated from Mount Aragats (Aragats Volcanic Province, AVP), one of the largest volcanoes in the Arabia-Eurasia continental collision zone. Here we report paleomagnetic results, in combination with anisotropy of magnetic susceptibility (AMS) analysis, from 31 outcrops belonging to six ignimbrite units of the western part of the AVP (covering an area of more than 5000 km2). Paleomagnetic directional analysis of samples from 26 outcrops of the three younger ignimbrite units yields a well-defined normal polarity direction of D = 339.2°, I = 55.7°, k = 278.4 and α95 = 1.7°. The virtual coincidence of paleomagnetic directions points to an emplacement of the units within a restricted time of similar geomagnetic secular variation (i.e., few hundred years). However, new isotope 40Ar/39Ar ages of the three units suggest two separated events at ~0.65 and ~ 0.75 Ma. The possibility of similar paleomagnetic directions at 0.65 and 0.75 Ma or the occurrence of a widespread remagnetization event at 0.65 Ma cannot be fully excluded, but both scenarios are highly unlikely. In contrast to that, five sites from the three older units show reversed magnetic polarity, which implies an age of emplacement older than the last magnetic polarity reversal at ~780 ka. This agrees with recent 40Ar/39Ar ages of the three older units at ~0.93 Ma. The paleomagnetic scatter of the older units is high compared to the younger ones. Even if paleomagnetic directions and radiometric age are similar, available data cannot unequivocally indicate if the three older units were generated from the same or three different eruptions. The high quality AMS data result in three different types of fabric (lineated, foliated and undetermined) that are all commonly observed in the studied pyroclastic deposits. Accordingly, we use lineation, tilt of foliation, or both for the determination of paleoflow direction. Results reveal a radial flow pattern surrounding Mt. Aragats, which is, however, highly influenced by topographic features, such as valleys, even in proximity of the eruption center.

IDENTIFICATION OF GEOMORPHOLOGY AND LITOLOGY BASED ON ANALYSIS OF LANDSAT-8 SATELLITE IMAGES IN PADANG CITY

The application of remote sensing to obtain better quality and up to date maps is needs to be done through the utilization of lithology and geomorphology in mapping of Padang city. This study aims to obtain a lithological and geomorphological picture of the appearance of Landsat-8 OLI Composite 567 satellite imagery. The research method was carried out by image interpretation data preparation. The results showed the city of Padang has 2 units of landforms from visual interpretation, namely fluvial and denudational landforms. Lithology identification in Padang using geological imagery and maps as a reference succeeds to acquire geological and lithological units, namely: Alluvial Fan which is smooth texture, lowland topography, hue and color is bright, parallel river flow patterns, sparse vegetation, river area associations. Non-decomposed flow texture is rather rough, hilly topography, hue and color is dark, radial river flow patterns, dense vegetation, associated with forests. Andesite has a rather rough texture, highland topography, hue and color is dark, radial river flow patterns, dense vegetation, associated with mountainous terrain. Alluvial is found in coastal areas, lakes and sandy areas, fine texture, lowland topography, alongside large rivers with valley, has a bright color and hue, its flow patterns are parallel, sparse vegetation, river area associations. Hardened Crystal Tuff with a rather rough texture, topography in mountainous areas, hues and color is dark, radial river flow patterns, dense vegetation, hill area associations. Volcanic Rock has a rough texture, high terrain topography, has dark colors and hues, radial river flow patterns, has dense vegetation, and is associated with mountains.