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A comprehensive CFD-based erosion prediction procedure developed previously is applied to predict erosion in a 90° sharp bend. This paper serves as a further validation of the proposed Computational Fluid Dynamics (CFD) based erosion prediction procedure for a different geometry, flow and particle conditions to examine the generalization of this comprehensive CFD-based approach to other geometries. Special emphasis is played on the strong effects of the grids on the resulting erosion profile representation. Detailed meshing information is provided for repeatable and further improved CFD studies in future. In the process, erosion predictions for both large (256 μm ) and small particles (25 μm ) in a sharp bend geometry are performed by applying the comprehensive CFD-based erosion prediction procedure. Results are compared with data from the literature and are found to be in a good agreement with data which demonstrates the success of the applied CFD-based erosion prediction procedure. It is shown that appropriate meshing, selection of turbulence model and near wall modeling approach are crucial for obtaining good erosion prediction results utilizing CFD, especially for small particle erosion prediction under the present flow and geometry conditions.

How and up to what extent can the alteration in a surface caused by eroding particles affect the flow and/or erosion in subsequent time-steps? These are the questions that the current work seeks to address. For this purpose, a pseudo-transient 3D Computational Fluid Dynamics (CFD) model was adopted to investigate solid particle erosion in a submerged jet impingement geometry under liquid-solid flow conditions. The change in the shape of the surface was accounted for through dynamic deformation of the solid wall surface and computational mesh based on local erosion rates at regular time intervals. In this case, as particles impacted the surface, the erosion magnitudes at different locations were calculated and the surface profile and CFD mesh were correspondingly modified and then, the flow solution was updated. It was noticed that the transformation in specimen surface altered the particle impact characteristics and thus, the erosion rates.

Solid particle erosion is one of the key issues affecting operational reliability and cost of tools and equipment in the oil and gas industry. Solid particles are typically either entrained in the fluid stream as a part of the unfiltered solids during drilling and production operations or are intentionally added to the fluid and transported into the formation during hydraulic fracturing. Erosion rates of optimized and suboptimal equipment designs can differ by several orders of magnitude. Recent developments in computational fluid dynamics (CFD) have led to the development of methodologies enabling accurate erosion wear life prediction. The study includes an overview of best practices in erosion prediction and shows practical examples of their application based on experimental studies of viscous slurry erosion in a direct impingement jet. Additionally, a Cross rheological model is used to model the non-Newtonian behavior of the fluid from the experimental program. The results show that the Cross model predicts a shear-thinning behavior; thus, erosion prediction with this rheological model agreed better with data than a Newtonian model.

Predicting more accurate sand erosion rate in oil and gas production is important for maintaining safe and reliable operations while maximizing output efficiency. Computational fluid dynamic (CFD) is a powerful tool for erosion prediction and provides detailed erosion pattern in complex geometry. To improve accuracy of erosion prediction, first part of this paper proposes an algorithm to include the effect of dynamically changing pipe geometry in CFD based erosion modelling and second part of this paper provides guidelines for proper treatment of turbulence dispersion in CFD based erosion modelling. Sand erosion is a time-dependent phenomenon where most severe erosion scars are localized and occurs under disturbed flow conditions. These localized high erosion rates cause substantial change in pipe geometry, creating cavities which modify the flow field, the particle trajectories and eventually the erosion pattern. This work has illustrated that the erosion prediction can be influenced by including the effect of dynamically changing pipe geometry in CFD modelling. An algorithm was developed to couple erosion rate calculations with a Moving-Deforming-Mesh, which dynamically deforms the solid wall surface geometry and computational mesh based on the local erosion rate at regular time intervals. This effect will be significant for geometries involving sharp corners and/or regions of recirculation zones. Sand erosion largely depends on particle impact location, impact angle and impact velocity - which is the commutative effect of particle trajectory leading to the bounding surface. The particle trajectory is determined based on mean and the turbulence of the flow field. In steady state CFD simulations with Reynolds Averaged Naiver Stokes (RANS) turbulence models, turbulent dispersion is obtained from mean turbulence quantities using a stochastic random walk model, which estimates the instantaneous characteristics of a turbulent eddy. However, stochastic random walk model parameters will have significant effects on turbulence dispersion of the particles and hence the erosion prediction. Specific guidelines for these model parameters can improve the accuracy and consistency in CFD based erosion prediction.

A comprehensive CFD-based erosion prediction procedure is applied to predict erosion in two elbows mounted in series. First, different CFD models are evaluated with sand fines (28 μ m ) erosion data from Kumar et al. [1] for two horizontal-horizontal 2 in. short radius elbows mounted in series. The effects of turbulence model and particle rebound model are examined to obtain the most appropriate model combination for running erosion simulation. A systematic grid refinement study is also conducted for the geometry with application to sand fines (28 μ m ) erosion prediction. In the process, it is found that erosion prediction for sand fines can be significantly affected by grid configuration due to current limitations of CFD codes. Finally, the paper proposes a meshing strategy that is capable of capturing sand fines dispersion and transport which is highly recommended for use to run erosion simulations especially for predicting small particle erosion using current commercial CFD codes.

The influence of rotating particles on surface damage should be considered to improve the accuracy of erosion prediction. In the present study, numerical simulations were carried out to investigate the wear morphology and stress distribution of a target material subjected to rotating particle impacts. A new experimental method was established to validate the model. The model was then used to study the influence of rotating particle impacts at different impact velocities and angles on wear behavior of the material. Correlation between the severity impact wear and particle rotation was observed and quantified. The results show that rotation of solid particles impacting a material can significantly affect the magnitude and pattern of impact wear. Particles with a forward spin were found to promote forward movement of the material surface, whereas particles with a backward spin contributed to vertical deformation of the material. Finally, impact wear profiles produced by different particles with different rotation modes were compared. These results provide insights into the damage mechanism of rotating particles and a theoretical basis for further investigations.

Computational Fluid Dynamics (CFD) based erosion prediction procedures are carried out to predict erosion for a submerged liquid jet impingement geometry. 3-D modeling with different near wall treatments are employed to simulate the wall bounded turbulent jet flow. Discrete Phase Model (DPM) is applied to track particles and obtain particle impact characteristics. Erosion is calculated using typical erosion ratio equations in the literature (Zhang et al., 2009) [1]. In this paper, two categories of near wall modeling approaches (wall functions and near wall models) are presented and examined. Particle impact parameters are extracted and compared with measured data to determine the most accurate near wall modeling approaches. A procedure for grid refinement particular for erosion simulations is proposed and followed by uncertainty analysis from the CFD predictions. Experimental data with uncertainty quantified for 300 μ m large particles and 25 μ m small particles are utilized to validate the proposed procedure. It is shown that following the proposed procedure yields very good erosion prediction from CFD regardless of particle size.

Computational fluid dynamics (CFD) is a useful tool to predict the erosion behaviour over geometries exposed to conditions of severe erosion wear. This work shows how CFD can be used to virtually characterize the wear behaviour of materials used in several hydraulic components, including turbomachinery systems, in which it is important to consider the effect of particle size. In addition, this work develops a methodology for determination and validation of the constants involved in the well-known Tabakoff-Grant model for erosion prediction using the erosion wear obtained via erosion testing in a jet tribometer reported in the literature as a reference. From the experimental data, an optimization algorithm was performed to determine the optimal values of Tabakoff-Grant model constants for ASTM A743 grade CA6NM martensitic stainless steel. The simulated erosion rate agrees with the experimental data for the material analysed in jet erosion simulations with impact angles ranging from 15° to 90°. The change of the angle of maximum erosion rate for small particles, which has been reported in the literature via experimentation, was explained satisfactorily. The results showed that the erosion rate with smaller particles is affected by fluid flow, since small particles tend to follow the flow streamlines, while larger particles move according to the conditions imposed by the jet at its outlet. The effective impingement angle against the surface for small particles is lower than the impingement angle for large particles; therefore, the angle of maximum erosion rate, measured between the jet and the sample's surface, for small particles increases.

Erosive wear due to solid particle impacts is a significant challenge in process industries, especially for oil and gas industries where multiphase flow with the presence of solid particles conveyed by the fluid is very common. Solid particle erosion is a complex phenomenon with multiple factors contributing to its severity. Based on available studies in the literature, mechanistic and empirical erosion models are available that are being used by investigators to predict erosion in complex geometries. The erosion models require particle impact speed and angle to be determined for predicting solid particle erosion. Thus, in many applications, Computational Fluid Dynamics (CFD) codes are used to track the trajectories of solid particles to model erosion in complex geometries. However, the problem of predicting erosion in complex geometries where rebounded particles can have a significant effect on erosion pattern has been addressed only by a few investigators in the literature. The complexity results from the fact that trajectories of rebounded particles and their resulting velocities must be determined. The current investigation uses experimental data and modelling to determine the effects of particle rebounds on erosion patterns. The experimental setup is composed of two stainless steel and aluminum specimens at a right angle to each other, and the angle between the nozzle and first specimen is 45 degrees. The second specimen is painted to determine the erosion pattern caused by rebounding particles from the first. The effects of material composition and surface roughness on the rebounding particles are presented. Additionally, a mechanistic rebound model describing the erosion pattern, erosion intensity and location of maximum erosion is presented, and the predictions are compared with experimental data. It is found that the rebound model has a great influence on erosion prediction especially where subsequent particle impacts are expected. It is also shown that the existing empirical rebound correlations in the literature are not effective for erosion calculation purposes.

Ultrasound technology is a promising technique for wastewater treatment. However, its industrial application and scale-up face numerous problems, such as ultrasonic horn tip erosion. In solid–liquid flow systems, the synergy between cavitation and solid particle erosion is unclear, and the influence of solids motion is relatively unknown. By analyzing the tribosystem near the tip surface, we hypothesize that the synergistic erosion depends on the flux of solid particles flowing past the surface, relating to the local solids concentration and velocity. This hypothesis was investigated by ultrasonic cavitation–particle erosion tests performed in an eccentrically agitated tank. To study the effect of local concentrations and velocities, we carefully controlled the total solids and impeller speeds by integrating their coupled influence. Results indicate that synergistic erosion was aggravated at higher solids concentrations and velocities, and both parameters, based on a sensitivity analysis, show similarities in their relative degree of influence on erosion. This supports our hypothesis, which unifies the two parameters into a single factor, and explains the synergism in solid–liquid flows. Understanding these influencing factors and mechanisms will contribute to erosion prediction and the optimization of ultrasound applications in wastewater treatment processes.

A new dimensionless number for erosion prediction in standard elbows under gas-liquid-solid flow conditions is developed. For this purpose, a machine learning algorithm is trained and used to generate erosion data. Then, three important dimensionless groups are extracted employing dimensional analysis. Next, self-similarity is established among these groups and a new dimensionless number ( P n r T P ) is developed. It is revealed that erosion can be predicted through mixture Reynolds number for different flow regimes, when the deviation from the homogenous no-slip conditions is accounted for. Furthermore, validation is performed against different experimental data for a wide range of flow and particle conditions.

The synergy between cavitation erosion and solid particle erosion fascinates tribologists owing to the contradicting roles of microparticles in aggravating or alleviating erosion. Based on an effective-medium approach, we develop a theoretical model to predict synergistic erosion, which incorporates the influence of suspension viscosity on bubble/particle dynamics and the impact energy of erosive particles. The model was experimentally validated, with strong agreement between the model predictions and experimental results. Further analysis shows that the viscous effect of silt-sized particles (STPs, 50 μm). The critical sand-to-silt ratio—the SDP/STP ratio that results in the same material removal as that in the solids-free case—is found to be a key parameter in the prediction of the synergistic erosion. The model embodies the opposing effects of microparticles on the cavitation erosion, and shows promise for erosion prediction and prevention.

Computational fluid dynamics (CFD) is a useful tool to predict the erosion behaviour over geometries exposed to conditions of severe erosion wear. This work shows how CFD can be used to virtually characterize the wear behaviour of materials used in several hydraulic components, including turbomachinery systems, in which it is important to consider the effect of particle size. In addition, this work develops a methodology for determination and validation of the constants involved in the well-known Tabakoff-Grant model for erosion prediction using the erosion wear obtained via erosion testing in a jet tribometer reported in the literature as a reference. From the experimental data, an optimization algorithm was performed to determine the optimal values of Tabakoff-Grant model constants for ASTM A743 grade CA6NM martensitic stainless steel. The simulated erosion rate agrees with the experimental data for the material analysed in jet erosion simulations with impact angles ranging from 15° to 90°. The change of the angle of maximum erosion rate for small particles, which has been reported in the literature via experimentation, was explained satisfactorily. The results showed that the erosion rate with smaller particles is affected by fluid flow, since small particles tend to follow the flow streamlines, while larger particles move according to the conditions imposed by the jet at its outlet. The effective impingement angle against the surface for small particles is lower than the impingement angle for large particles; therefore, the angle of maximum erosion rate, measured between the jet and the sample's surface, for small particles increases.

Erosion damage is common in many industries and one of the flow components which may experience severe erosion rates is choke geometry. Choke valves in wellhead or well completion may experience such conditions. In the present study, Computational Fluid Dynamic (CFD) was employed to calculate erosion for a choke geometry constructed of aluminum. The Eulerian-Lagrangian approach was utilized for continuous and discrete phase calculations in which different turbulence models were implemented to investigate the importance of erosion mechanisms in the choke geometry. Meanwhile, various erosion models were examined to achieve accurate erosion prediction. Afterward, two modifications in the geometry were made to see how erosion will be changed in different sections. It was revealed that the modifications can affect the dominating erosion mechanisms and newly designed profiles can reduce the erosion rate in different parts of the geometry significantly. Finally, erosion rate for carbon steel material which might be found in the oil and gas production systems was compared with the one of original aluminum case and it was found that thickness loss rate for the carbon steel case is one-third of the aluminum one in the most parts of the choke and much smaller on contraction plane.

Foundations of methodology and the calculation tool for prediction of cavitation erosion performance of elasto-plastic materials are presented. Probabilistic phenomenological model for quantifying the process and experimental results of the International Cavitation Erosion Test were used to develop the tool as an application of the erosion prediction method. It comprise implementation of the model accompanied with phenomenologically derived formulas for discovering the parameters included. Necessary input data to its activation refer to loading value and target specifications, including strength parameters of the material. Having been completed, the system may serve as a tool for simulations of the cavitation erosion performance as solid volume loss in the time domain.

Using an Eulerian–Lagrangian approach, numerical erosion modeling of a 90° sharp bend in water–sand slurry flow is performed. The numerical results are validated with experimental data in the literature [1] . Two different sand types, 25 µm sharp silica sand and 256 µm rounded quartz are used. The carrier fluid velocity is varied from 15.2 m/s to 26.2 m/s. The total mass loss and local wall thickness loss in upstream and downstream sections of the sharp bend are calculated and compared with experimental data. Two models are employed for resolving the near wall region, standard wall-function and low- Re number approach. It is found that for large particles (256 μm) the erosion results predicted by both models agree well with experimental data. However, using the standard wall function for small particles (25 μm) produces non-physical particle trajectory near the wall. This leads to over prediction of experimental data by about one order of magnitude. The numerical results show that adequately resolving the near wall region and employing the low- Re number model can significantly improve the erosion prediction resulting from small particles.

Erosion of surfaces is an on-going industrial problem wherever solid particles are conveyed. The literature reveals very limited data reported for elbow erosion. Almost all data that is available only relates to the elbow extrados, or else provides an overall mass loss of surface material with no information on erosion distribution. A detailed surface map of erosion depth in a standard elbow (90° bend, with bend radius to pipe diameter ratio equal to 1.5) is presented using measurements taken with a surface profiler. The full erosion data map is reported on a 40×20 point grid for erosion caused by the passage of 200 kg and 300 kg of sand through the elbow. The sand had a median diameter of 184 μm, and was conveyed by room temperature air travelling at 80 m s−1. Numerical modelling of the erosion distribution is then performed using the conventional Euler–Lagrange approach to erosion prediction. It is found that the use of this approach, in combination with a smooth wall assumption for particle–wall collisions, leads to inaccurate prediction of maximum erosion depth together with a characteristic “vee”-shaped erosion scar that is not present in the experimental data. By adopting a suitable rough wall collision model the erosion depth and distribution are much more accurately predicted. However, particle shape, surface profile development and surface roughness development are all factors that may also affect the erosion pattern. The numerical modelling demonstrates the importance of accurately incorporating particle–wall collisions, as well as other more complex flow behaviour, into the simulation if a true prediction of the erosion distribution is to be captured.

The prediction of erosion damage caused by solid particles within flow lines is crucial for many industries. In most erosion modeling approaches, empirical erosion equations are commonly used to relate particle impact information to erosion magnitude. These equations are usually generated from jet impingement testing in air, since the particle impact speed and angle are assumed not to deviate from conditions in the jet. However, in slurry flows, a wide range of particle impact angles and speeds are produced on the target surface. In this work combining CFD simulation results with experimental data obtained from a normal slurry jet test, an erosion equation has been developed. In this methodology, a computational fluid dynamics (CFD) simulation is used to characterize the particle impact speed, angle and frequency at specific locations on the specimen. Then, the particle impact data are related to the measured erosion depth to achieve an erosion equation from submerged testing. The erosion equation has been validated for oblique impingement configurations and it has been shown that, the equation is well suited for various test conditions and it can successfully predict the local erosion depth. Furthermore, a series of dry impinging jet tests for normal and oblique configurations has been performed. Utilizing a particle image velocimetry (PIV) technique, the slip velocity between the gas and sand particles has been determined. In order to gain a better understanding of the erosion pattern, local erosion depth has been measured using a 3D surface profilometer. The effect of gas velocity and impingement angle on erosion profile has also been investigated.

A numerical procedure is carried out to forecast the penetration rates of metal elbows caused by silica sand particles under air-water annular flow conditions. The procedure aims at overcoming the disadvantage of the existing numerical methods, which oversimplified the thickness distribution of the liquid film flowing through the elbows. The numerical procedure contains the steps of solving the flow field, tracking the particle response and calculating the collision damage. The core mixture in the pipe is taken as one homogeneous phase when solving the flow field. The drag force and turbulent dispersion force are calculated when tracking the particles in the core region. When tracking the particles in the liquid film, the specific film thickness at every given position of the elbow is introduced into the calculation. After calculating the particle-wall impact information, the penetration rate of the elbow is obtained by introducing the correlation which can calculate the collision damage of various metal materials. The numerical procedure is verified through the comparison between the typical experimental data and the predicted results. Several empirical and semi-empirical erosion prediction models are compared with the present procedure on the accuracy. The effects of the main factors on the penetration rate are investigated in the parametric studies. The thickness distribution and velocity of the liquid film considerably influence the effective collision intensity of the particles. By using the complete thickness information of the liquid film, the present procedure shows good accuracy in estimating the erosion of elbows under annular flow conditions.

In the oil and gas and other process industries it is necessary to have accurate and versatile methods of determining surface erosion rates, and to use them to predict the erosion of surfaces over time. In this work a combined experimental and computational study has been performed to examine and predict the erosion characteristics on a simple flat aluminium plate, with a central hole, that is impacted with silica sand. Existing techniques were employed to generate very accurate experimental data for calibration of a computational erosion sub-model. This sub-model was then incorporated into a computational fluid dynamics environment to predict erosion on the flat plate. It was found that profile development on bluff surfaces could be predicted with accuracy generally much less than a nominal maximum deviation of 30%. Erosion of the more complex aspects of the geometry was only qualitatively predicted. The importance of allowing for the erosion incubation period in calculations is demonstrated, and methods for improving erosion prediction of complex geometries are discussed.

An erosion prediction method with the objective of determining wear profiles on various geometries due to slurry erosion, based on material wear data acquired from a minimum set of carefully selected laboratory tests and CFD (computational fluid dynamic) simulations has been developed. Data from a single standard laboratory test [Jet Impingement Test on a flat specimen oriented at 90° to an impinging solid suspension (water and sand)] is characterised using CFD to acquire wear data for a range of erosion parameters as a function of position. This data is used to build a wear map for that specific material–abrasive (316L steel-AFS50/70 sand) combination. The accuracy of this method is assessed by predicting wear from further jet impingement tests at 90° but under different flow velocities to that used to build the map and subsequently assessing against experiments. A good correlation between predicted and measured wear was observed. An assessment of two phenomenological wear models (which profess to capture wear characteristics as a function of material properties) and one wear model that captures the above wear map statistically through the use of appropriate fitting functions is made.

The Research Committee on Cavitation Erosion in the Turbomachinery Society of Japan has already reported the prediction method of cavitation erosion rate. However, the scattering between the predicted rate and the measured rate is 100 times. In this study, we compare fundamental data of stainless steels collected by the Committee with the data obtained in our laboratory. The influence of material and liquid parameters on the scattering of the Committee data is discussed. We found that the scattering was influenced by high liquid temperature, the kind of liquids, the microstructure of components and the operating life. We propose a modified prediction equation including these parameters, and found that the equation improve the accuracy of the erosion prediction.

The pumping of fracturing slurry through coiled tubing can cause considerable wear of tubing and is an issue of industrial concern, both from safety and economic considerations. In hydraulic fracturing operations employing coiled tubing, the tubing wall is affected by non-uniform erosion for the section of the tubing spooled on the reel. The non-uniform wall erosion is caused by the centrifugal forces when pumping slurries at high rates. In spite of the large number of fracturing jobs performed in the industry today, research in this area of investigating and evaluating erosion has been limited. A computational fluid dynamics (CFD) study is undertaken to investigate the major contributing factors affecting erosion. The mechanisms leading to the erosion process have been discussed and erosion rate has been investigated as a function of flow rate, slurry concentration, proppant (solid particles) size and density, and fluid viscosity. This study utilizes both experimental tests and CFD simulations to investigate erosion in coiled tubing. The experiments have been conducted on a full-scale test facility at the Well Construction Technology Center (WCTC), The University of Oklahoma. CFD simulations have been conducted by utilizing erosion prediction and particle tracking modules in a commercial CFD code FLUENT. It is found that erosion phenomenon in coiled tubing is highly non-uniform with tubing extrados (external radius) being more susceptible to erosion as compared to intrados (internal radius). Results from CFD simulations established slurry flow rate to be the most significant factor affecting erosion. Slurry concentration and fluid viscosity are also found to influence erosion rate greatly.

Elbows, that are integral part of piping systems, are vulnerable in erosive environments. Plugged tees are used in industrial practice to replace elbows when erosion is expected. However, it remains unclear that plugged tees reduce erosion. Thus, this paper investigates the relative erosion severity between plugged tees and elbows for dilute gas/solid two-phase flow where the pressure is close to the atmospheric pressure. A computational fluid dynamics (CFD) based erosion prediction model was applied to predict the relative erosion severity. Experimental tests were conducted to verify the simulation results obtained for gas/sand flows. The ratio of erosion at the end of the plugged section to that in an elbow was found to approach a constant value for a range of conditions. A correlation is presented that provides the ratio of erosion of the outer downstream corner of the plugged tee to that in an elbow. The significant effect of sand loading on the relative erosion severity was discussed. The influence of phase density (e.g. water/sand flow) was preliminary explored.

We predict the erosion rate of unknown cannon tubes by substituting measured values of the standard cannon, 155 mm Howitzer M185, and ballistic data for the erosion equation. We know 10 measured erosion values of the standard cannon at every 400 rounds. An approximate formula is derived to interpolate five values up to 2000 rounds. The results of the simulations are analyzed. The new erosion equation is also suggested. This equation produces more accurate cannon tube erosion rate than the Rauf Imam’s empirical approaches. Numerical results are presented.

The modeling of particle–wall impaction in a confined gas-particle flow using both Lagrangian and Eulerian approaches is reported. The Lagrangian method is based on a general computational fluid dynamics (CFD) code, FLUENT (FLUENT-4.3, 1996). In the Eulerian method, based on our previously developed code [J. Eng. Gas Turb. Power 119 (1997) 709], a computational procedure by decomposing one Eulerian solution of particulate phase into two equivalent Lagrangian solutions for incident and reflected particles has been developed. These two approaches are evaluated versus experimental data for particle–wall impaction using spray droplets. Two test cases, a 45° ramp and an isolated single tube, have been studied using the above two approaches to determine the particle behavior and physical properties of impacting and reflected particles near wall surface. Results show that both approaches are successful in predicting the main features of particulate flow near wall, however, the Eulerian approach is much less expensive than the Lagrangian approach in obtaining the flow solution of impacting particles. The particulate flow predictions using both approaches have been applied for predicting tube erosions that are compared with reported data. Good agreement between predictions using the two approaches and between the predicted and measured erosion results are observed.

A survey of the existing erosion theories and their agreement with test results on erosion of pure metals and carbon steels is presented. It was found that the best correlation can be achieved with the use of Beckmann and Gotzmann's erosion theory. The program for computing the erosion rate of metals is based on the modified Beckmann and Gotzmann model. The respective data bases for most common abrasives and steels have been prepared. This program allows the prediction of the erosion rate over the range of impact angles from 0° to 90° and impact speeds from 10 to 200 m s−1 with an overall accuracy of ±30% for annealed and heat treated carbon steels and ±50% for pure metals.