Surface Speed Research Articles

Stokes layers in complex fluids

Stokes’s second problem is reconsidered for three models of complex fluids: an elasto-viscoplastic fluid, a thixotropic viscoplastic fluid and a discontinuously shear-thickening fluid. In each case, the Stokes-layer dynamics is interrogated with a view to examining the signatures of the detailed rheology. Significant deformations are possible below the yield stress for elasto-viscoplastic fluids as a result of the excitation of elastic waves, particularly near resonances. Thixotropic fluids with viscosity bifurcations layer internally, but surface-speed signatures mostly appear similar to those for simple yield-stress fluids. Stokes-layer oscillations of discontinuous shear thickening fluids can prompt abrupt increases in viscosity, introducing sudden jumps in surface speed. Pre-existing experimental results for layers of kaolin slurries in a motorized, oscillating tray are reconsidered and compared with the results for elasto-viscoplastic and thixotropic fluids.

Investigating the effect of nanobubble-based cutting fluid on tool wear and cutting forces in milling of Inconel 718

Machining of Nickel-Based Superalloys (NBSAs) is characterized by rapid work hardening, low thermal conductivity, and extreme abrasive behavior. Due to such characteristics of NBSAs, the machining of materials like Inconel 718 (IN718) results in extensive tool wear and high cutting forces. The present study employs nanobubble-based cutting fluid during machining of IN718 and investigates its effect on tool wear and cutting forces. The trochoidal milling experiments were conducted on an IN718 workpiece with nanobubble-based and normal cutting fluid at varying surface speeds. The evolution of tool flank wear area and peak resultant cutting force were recorded and compared to evaluate the effectiveness of nanobubble-based cutting fluid over normal cutting fluid. The results showed that nanobubble-based cutting fluid lowers the tool wear rate by enhancing heat dissipation and reducing abrasion wear. However, higher cutting forces were observed with nanobubble-based cutting fluid due to increase in hardness of the workpiece. Also, it is realized that using nanobubble-based cutting fluid can significantly improve the lifespan of the tool, leading to sustainable manufacturing.

Investigation of airflow thermal ice melting process under various flight conditions

The challenge of preventing and removing ice from exposed regions of aircraft is a significant engineering concern. Understanding the melting process of ice due to aerodynamic heating during flight is essential for developing UAV flight strategies in icy conditions. This paper analyzes the heat transfer mechanisms involved in airflow over ice and introduces a theoretical model to estimate the ice melting rate, using principles of turbulent heat transfer at the stagnation point. The study also discusses the impact of environmental conditions on ice melting rates. Findings indicate that the melting speed of the ice surface exhibits a negative linear correlation with the initial temperature of the ice, whereas it shows a nonlinear correlation with airflow velocity and total temperature of the incoming flow. Lower airflow velocity or total temperature of the incoming flow enhances the sensitivity of ice melting speed to changes. Additionally, lower ice density results in a higher melting speed, showing an exponential relationship with factors like average droplet diameter, airflow velocity, and airfoil leading edge diameter in the cloud field during icing. Experiments conducted using a small jet test bench and an icing wind tunnel confirmed the impact of varying conditions on ice melting rates. The deviation between experimental results and theoretical predictions was under 5 %. These conclusions offer valuable insights for flight safety planning of unprotected iced aircraft in challenging environments.

Data driven digital twin system for the cross-domain vehicle

The Cross-Domain Vehicle (CDV) is a sophisticated marine equipment capable of performing tasks across different domains. This paper aims to develop a data-driven digital twin system for the CDV to achieve precise motion control and data monitoring during its operation. Leveraging the kinematic physical characteristics of the CDV, the digital twin system constructs a virtual counterpart of the vehicle, establishing a mapping relationship between the physical and virtual entities. The use of a Long Short-Term Memory (LSTM) network model is proposed for forecasting the motion state of the CDV within the digital twin framework, supporting the vehicle's autonomous motion decision-making process. Additionally, an innovative model predictive control strategy is employed to achieve surface speed tracking control for the CDV, leveraging predictive data within the digital twin system. Utilizing the digital twin system to optimize control parameters, better underwater depth control effects can be achieved for the CDV. Finally, through the system implementation and experiment verification, the effectiveness of the digital twin system is successfully demonstrated, providing reliable results for both surface speed tracking control and underwater depth control.

Effect of variable load on centralized dimple in opposite sliding condition

Abstract In ball bearings without a cage, adjacent balls exhibit a zero-entrainment velocity (ZEV) contact condition, which is worse than typical pure rolling or rolling-sliding contact, and the contact between adjacent balls under periodic loading is notably more complicated. In this work, thermal elastohydrodynamic lubrication (EHL) numerical calculation is carried out under the condition of periodic impact and opposite sliding line contact over a wide range of surface speeds. the pressure is solved by multigrid method, the elastic deformation is evaluated using multigrid integration method, the temperature field is calculated by column-by-column scanning technique. The results show that the loading-unloading process exerts significant influence on the variation of the centralized dimple, pressure, and temperature rises as well as the oil characteristics. With the increase of surface speed, the effect of load fluctuations diminishes, and the central dimple exhibits the following evolutionary trend under ZEV conditions: no dimple at very low velocity - small central dimple - large typical dimple - no dimple at high velocity. The result indicates that under the ZEV condition of EHL stage, elevated velocities decrease the coefficient of friction and augment the film thickness.

Sensitivities of the West Greenland Current to Greenland Ice Sheet Meltwater in a Mesoscale Ocean/Sea Ice Model

Abstract Meltwater from the Greenland Ice Sheet can alter the continental shelf/slope circulation and cross-shelf freshwater fluxes and limit deep convection in adjacent basins through surface freshening. We explore the impacts on the West Greenland Current and eastern Labrador Sea with different vertical distributions of the meltwater forcing. In this study, we present the results from global coupled ocean/sea ice simulations, forced with atmospheric reanalysis, that are mesoscale eddy-active (∼2–3-km horizontal spacing) and eddy-permitting (∼6–7-km horizontal spacing) in the study region. We compare the West Greenland Current in mesoscale eddy-active and eddy-permitting without meltwater to highlight the role of small-scale features. The mesoscale eddy-active configuration is then used to assess the change in the eastern Labrador Sea when meltwater is added to the surface or vertically distributed to account for mixing within fjords. In both simulations with meltwater, the West Greenland and West Greenland Coastal Currents are faster than in the simulation with no meltwater; their mean surface speeds are the highest in the vertical distribution case. In the latter case, there is enhanced baroclinic conversion at the shelf break compared to the simulation with no meltwater. When meltwater is vertically distributed, there is an increase in baroclinic conversion at the shelf break associated with increased eddy kinetic energy. In addition, in the eastern Labrador Sea, the salinity is lower and the meltwater volume is greater when meltwater is vertically distributed. Therefore, the West Greenland Current is sensitive to how meltwater is added to the ocean with implications for the freshening of the Labrador Sea. Significance Statement Our goal is to understand how the flux of freshwater across the West Greenland continental slope into the Labrador Sea is modified by meltwater from the Greenland Ice Sheet. We compare the simulations of the ocean that capture key dynamics along the West Greenland continental slope that have no meltwater, meltwater added to the ocean surface, and meltwater distributed vertically to represent the mixing within fjords. When meltwater is added, the currents along the continental slope are faster, with the greatest increase when meltwater is vertically distributed. In that case, there is enhanced freshening of the Labrador Sea because modified density gradients generate more eddies. Proper representation of the vertical structure of meltwater is important for projecting the impact of freshwater on the subpolar North Atlantic.

Rapid Failure of Lubricated Contacts with Grease Under ZEV Condition

Abstract In response to the rapid failure of grease lubrication under low surface speed with zero entraining velocity (ZEV), a common occurrence in ball screws or retainerless rolling element bearings, detailed observations were conducted through optical interferometric experiments. It was observed that despite a constant surface speed and load, the motion remained transient due to the transition between outlet cavitation and inlet starvation. The reciprocating motion of the cavitation zone rapidly depleted the contact area, leading to severe surface peeling. However, as the surface speed increased, this phenomenon was alleviated and eventually disappeared. To enhance lubrication performance, bilateral grooves were created using laser technology, proving to be advantageous for grease lubrication life under low surface speed conditions. Despite the occurrence of rapid surface failure, grease lubrication demonstrated clear benefits over oil lubrication when operating at low surface speeds.

Research on the Milling Performance of Micro-Groove Ball End Mills for Titanium Alloys

Titanium alloys are widely used in various fields, but milling titanium alloy materials often leads to problems such as high milling forces, increased milling temperatures, and chip adhesion. Thus, the machinability of titanium alloys faces challenges. To improve the milling performance of titanium alloy materials, this study analyzes the effective working area on the surface of the milling cutter through mathematical calculations. We design micro-grooves in this area to utilize their friction-reducing and wear-resisting properties to alleviate the aforementioned issues. The effective working area of the ball end milling cutter’s cutting edge is calculated based on the amount of milling and the installation position between the milling cutter and the workpiece. By observing the surface structure of seashells, micro-grooves are proposed and designed to be applied in the working area of the milling cutter surface. The impact of the micro-groove area on the milling cutter surface and spindle speed on milling performance is discussed based on milling simulation and experimental tests. Experimental results show that the cutting force, milling temperature, and chip resistance to adhesion produced by micro-groove milling cutters are superior to conventional milling cutters. Milling cutters with three micro-grooves perform best at different spindle speeds. This is because the presence of micro-grooves on the surface of the milling cutter improves the friction state, promoting a reduction in milling force, while the micro-grooves also serve as storage containers for chips, alleviating the phenomenon of chip softening and adhesion to the cutter. When conducting cutting tests with a milling cutter that has three micro-grooves, the milling force is reduced by 10% to 30%, the milling temperature drops by 10% to 20%, and the surface roughness decreases by 8% to 12%.

An Exact Solution to the Inverse Problem of Steady Free-Surface Flow over Topography

A simple exact solution is presented to the inverse problem in steady, two-dimensional idealised flow over topography that seeks the bottom profile given knowledge of the free-surface data. Attention is focused on the case when a uniform stream flows over a localised obstacle, although the solution is not restricted to this case. The inverse problem is formulated as a Stieltjes integral equation which is solved exactly using a Fourier transform. The solution requires the analytic continuation of two real functions representing the surface speed and the angle between the surface velocity vector and the horizontal. Some example surface profiles and their corresponding bottom topographies are discussed. Although the solution requires the prescription of the surface as a function of the velocity potential, it is shown to closely resemble the corresponding profile in physical space, even for quite large surface displacements, while significant discrepancy occurs at the bottom. Inference of the bottom profile from discrete surface data is accomplished by way of polynomial interpolation and rational approximation in the complex plane for the sample case of a hydraulic fall.

DEVELOPMENT OF WOOD GRINDING. 6. SIGNIFICANCE OF THE FRICTIONAL COEFFICIENT IN GRINDING OF SPRUCE WOOD

The purpose of this study was to clarify whether the wood grinding model – based on an energy balance for the grinding zone – would improve understanding of wood grinding for pulp. This study relied on previously obtained data by the Finnish Pulp and Paper Research Institute. The frictional coefficient (Pc/Pt) computed and the power-specific groundwood production (Ġw/Pt) were important x- and y- variables, respectively. Fresh spruce wood samples were ground by application of a laboratory grinder, where the stone surface speeds were 30, 15 and 7 m/s, respectively. The power-specific productivities of high- and medium-speed grindings followed one and the same mechanism, since both speeds led to a productivity of 0.99 [(kg/h)/kW]; the low-speed grinding, however, led to a level of 0.66 [(kg/h)/kW] at frictional coefficients closest to 100 mW/kW. The rate of formation of coarse rejects was – at the same frictional coefficient as before – 15.0, 4.3 and 2.3 mg/s for high-, medium- and low-speed grindings, respectively. However, the rate of fines formation determined by McNett apparatus was about ten times higher than that of formation of coarse rejects: 123.0, 42.2 and 23.7 mg/s, respectively. The fines-to-shives ratio (determined by a Somerville shive analyser) was assumed to indicate fiberisation for high-, medium- and low-speed grindings, and the true data, most close to 100 mW/kW, were 56.0, 55.9 and 36.1 units of fines-to-shives, respectively. The curves followed the same trend, but on slightly different levels. As for the important sheet properties, the tensile strengths of high-, medium- and low-speed grindings were low, medium and high, respectively: 37.1, 46.9 and 56.2 Nm/g. The light scattering coefficients of high-, medium- and low-speed grindings were low, medium and high, respectively, or as data being most close to 100 mW/kW: 59.2, 66.0 and 67.5 m2/kg, respectively. Some general conclusions may be drawn from these results. To achieve the best groundwood productivity, the frictional coefficient should be kept on a level close to 100 mW/kW. Generally speaking, it seems that high- and medium-speed grindings appeared to act as following the same mechanism as far as the productivity was concerned, but the rates of shives and fines formation did not follow such a pattern. The groundwood sheets showed lower tensile strength in high-speed grinding than in medium-speed grinding, while the light scattering coefficient was much lower for the high-speed grinding than for the medium-speed grinding. Because of its low productivity, the low-speed grinding does not seem to be useful, although high tensile strength and high light scattering of the sheets would plead for it.

Model test study on the formation of basin-shaped freezing range in sandy gravel stratum under seepage conditions

The basin-shaped freezing method has a wide range of engineering application prospects because it is environmentally friendly and not sensitive to the depth of the phreatic layer. Based on the similarity theory, multiple sets of model tests were performed to study the development of the basin-shaped freezing range and analyse the influence of seepage velocity, the distance between the freeze pipes and the refrigerant temperature. The test results revealed that, under the influence of group pipe effect, the cooling rate in the middle of the basin bottom was the fastest, and the formation time was the shortest. A single factor had no noticeable impact on the formation time of the closed basin bottom. However, the formation speed of the top surface of basin wall was the slowest under the influence of boundary effect and was significantly influenced by various factors. When the basin wall freeze pipes were arranged with the same spacing along and perpendicular to the water flow direction, the formation time of the top surface of the basin wall perpendicular to the water flow direction was the longest. When the spacing of the freeze pipes along the water flow direction was greater than that perpendicular to the water flow direction, attention should be given to the temperature of the top surface of the basin wall in both directions. The empirical relationships between the formation time of the basin wall and the distance between freeze pipes and the seepage velocity were obtained through regression analysis.

THE RELATIONSHIP OF THE DISTRIBUTION OF SEA SURFACE TEMPERATURE WITH RAINFALL AND WIND IN THE WATERS OF WEST SUMATRA

This research was carried out in February-March 2023 in the West Sumatra waters. It aimed to determine the variability of sea surface temperature, rainfall intensity, wind direction, and speed in the West Sumatra waters. Sea surface temperatures were taken from three stations, namely: in the coastal waters of Pariaman City, Padang-Pariaman Regency, and Bungus, Padang. The survey method was used, which was directly observed in the field. The results showed that the Sea Surface Temperature of the study areas ranged from 29.25oC-30.28oC, while the rainfall went from 211.97-499.89 mm, and the dominant speed was between 0.50-2.10 m/s. The correlation analysis between rainfall and sea surface temperatures in Station 1 yielded an "r" value of 0.871, a powerful correlation category, and the determination coefficient (R2) was 0.579 or 57.9% during the western season. In the east season, the "r" value was 0.321, in the moderate correlation category, and the determination coefficient was 0.103 or 10.3%. At Station 2, the correlation coefficient (r) was 0.788, a powerful correlation category, and the determination coefficient (R2) was 0.622 or 62.2% during the western season. In the east season, the "r" value was 0.699, a strong correlation category, and the determination coefficient was 0.488 or 48.8%. At Station 3, the "r" value was 0.688, a strong correlation category, and the determination coefficient was 0.477 or 47.7% during the western season. In the east season, the "r" value was 0.743, a strong correlation category, and the determination coefficient was 0.579 or 57.9%

Road Surface Pits and Speed Bumps Recognition Based on Acceleration Sensor

Road Surface Pits and Speed Bumps Recognition Based on Acceleration Sensor

Spontaneous Formation of an Internal Shear Band in Ice Flowing Over Topographically Variable Bedrock

AbstractIce surface speed increases dramatically from upstream to downstream in many ice streams and glaciers. This speed‐up is thought to be associated with a transition from internal distributed deformation to highly localized deformation or sliding at the ice‐bedrock interface. The physical processes governing this transition remain unclear. Here, we argue that highly localized deformation does not necessarily initiate at the ice‐bedrock interface, but could also take the form of an internal shear band inside the ice flow that connects topographic highs. The power‐law exponent n in the ice rheology amplifies the feedback between shear heating and shear localization, leading to the spontaneous formation of an internal shear band that can create flow separation within the ice. We model the thermomechanical ice flow over a sinusoidal basal topography by building on the high‐resolution Stokes solver FastICE v1.0. We compile a regime diagram summarizing cases in which a sinusoidal topography with a given amplitude and wavelength leads to shear band formation for a given rheology. We compare our model results to borehole measurements from Greenland and find evidence to support the existence of an internal shear band. Our study highlights the importance of re‐evaluating the degree to which internal deformation contributes to total deformation in the ice column and to the flow‐to‐sliding transition.

Dynamic Light Scattering for the Measurement of Transport Properties of Fluids

The present article summarizes experimental and theoretical considerations required for a proper use of dynamic light scattering (DLS) for the measurement of transport properties of fluids. It addresses not only recent advancements of the method, but also aims to provide recommendations to researchers who intend to apply the technique in the future. As outlined in this study, DLS is based on the analysis of scattered light governed by microscopic statistical or periodic fluctuations that originate from the thermal movement of molecules and/or particles at macroscopic thermodynamic equilibrium. The dynamics of these hydrodynamic fluctuations in the bulk of fluids or at their phase boundaries are related to the underlying diffusive processes and, thus, to the associated transport properties, and are reflected by the time-dependent correlation function of the scattered light intensity. The fundamentals of this type of detection, known as photon correlation spectroscopy (PCS), will be discussed in the present contribution in some more detail. It is emphasized that the experiments need to be designed carefully in accordance with theory in order to assign the measurement signals to the corresponding hydrodynamic fluctuations. If the necessary conditions are fulfilled, DLS allows the accurate determination of several transport properties including kinematic and dynamic viscosity, thermal diffusivity, mutual diffusivity, and sound attenuation, which may be accessed together with other thermophysical properties such as speed of sound and surface or interfacial tension. In some instances, also the simultaneous determination of several transport properties is possible. With the exception of the sound attenuation, expanded uncertainties for the mentioned transport properties down to 1 % can be achieved for various types of fluid systems over a wide range of thermodynamic states up to elevated temperatures and pressures as well as in the vicinity of critical points. This performance and versatility of the DLS technique is documented in the present study by highlighting measurement examples from recent thermophysical property research on different classes of working fluids relevant for process and energy technology.

Characteristics and mechanisms of near-surface negative atmospheric electric field anomalies preceding the 5 September 2022, Ms 6.8 Luding earthquake in China

Abstract. A magnitude 6.8 strike-slip earthquake (EQ) struck Luding, Sichuan Province, China, on 5 September 2022, resulting in significant damage to nearby Ganzi Prefecture and the city of Ya'an. In this research, the near-surface atmospheric electric field (AEF) recorded at four sites 15 d before the Luding EQ was analyzed and differentiated, and multisource auxiliary data including precipitation, cloud base height, and low cloud cover were used at the same time. Nine possible seismic AEF anomalies at four sites were obtained preliminarily. Accordingly, microwave brightness temperature (MBT) data, which are very sensitive to the surface dielectrics and are closely related to the air ionization, together with surface soil moisture, lithology, and a 3D-simulated crustal stress field, were jointly analyzed to confirm the seismic relations of the obtained negative AEF anomalies. The geophysical environment for crustal high-stress concentration, positive charge carrier transfer, and surface accumulation was demonstrated to exist and to meet the conditions necessary to generate local negative AEF anomalies. Furthermore, to deal with the spatial disparities in sites and regions with potential atmospheric ionization, near-surface wind field data were employed to scrutinize the reliability of the AEF anomalies by comprehensively analyzing the spatial relationships among surface charges accumulation areas, wind direction and speed, and the AEF sites. Finally, four negative AEF anomalies were deemed to be closely related to the Luding EQ, and the remaining five possible anomalies were ruled out. A possible mechanism of negative AEF anomalies before the Luding EQ is proposed: positive charge carriers were generated from the underground high-stress concentration areas and then transferred to and accumulated on the ground surface to ionize the surface air, thus disturbing the AEF above the ground. This study presents a method for identifying and analyzing seismic AEF anomalies and is also beneficial for the examination of the pre-earthquake coupling process between the coversphere and the atmosphere.

Block processing time-based programming for high-speed, high-precision 5-axis machining

For high-speed and high-precision machining with orthogonal 3-axis minute line segment commands, a program should be generated by appropriately reducing the chord error (tolerance) or the block length (line segment length) based on the computer numerical control (CNC) block processing time Tb. The block processing time Tb is the duration from when the CNC decodes one block command in a program until when it controls the motors, depending on the processing power of the CNC. Accordingly, even in simultaneous 5-axis machining, it is necessary to research whether programs generated based on Tb can achieve high-speed and high-precision machining. Therefore, this study aims to realize simultaneous 5-axis machining at higher speed and precision using CNC programs with minute line segment commands based on Tb. In addition, we propose a more general identification method compared with that used in previous studies to identify Tb. Simultaneous 5-axis programs include two cases of control, namely, tool center point (TCP) control and Non-TCP control, and Tb was identified for both controls. For the machining method, using the block length based on Tb, we generated programs to machine the upper flat surface of a workpiece using simultaneous 5-axis machining while rotating the two rotary axes using a ball-end mill. We machined the workpiece and evaluated the machining speed and precision of the machined surface. We showed that simultaneous 5-axis machining with higher speed and precision can be achieved using programs based on Tb. In addition, we analyzed and considered the reasons for the higher-speed and higher-precision machining.

Distribution, trends and drivers of precipitation use efficiency in the loess plateau

AbstractAgainst the background of climate change, the global carbon and water cycle has undergone significant changes, and it is of great significance to explore the interrelationships of the carbon and water cycles in different regions to cope with future climate change. In this study, based on gross primary productivity (GPP) and precipitation (PRE) data, the precipitation use efficiency (PUE) of the Loess Plateau (LP) was calculated, and the Sen trend analysis and Mann‐Kendall test were used to analyse the temporal and spatial variation characteristics of PUE, as well as the first‐order difference method was used to derive the relative contributions to quantify the impact of vegetation growth and meteorological factors on PUE. The results show that (1) from 2001 to 2018, the spatial distribution pattern of vegetation PUE exhibited an increasing trend from northwest to southeast. On the time scale, the multi‐year average value of PUE was 1.17 gC m−2 mm−1, showing an overall upward trend. Among the different land cover types, paddy fields had the highest PUE level, and sparse grassland had the lowest; (2) LAI had the highest relative contribution to vegetation PUE, followed by temperature (Temp), net radiation of the ground surface (RN), specific humidity (Shum), and wind speed (WS). LAI contributes positively to 88.9% of the area. RN positively influences high‐altitude areas, while Shum had a larger area with a negative contribution. The contribution of Temp increases from northwest to southeast, and WS has balanced positive and negative contributions; (3) LAI is the dominant factor for the spatial and temporal variation of PUE in the LP, and the size of the areas where different meteorological factors dominate the changes of PUE are as follows: WS > Shum>RN > Temp. At high altitudes, the dominant meteorological driver is WS, while at low altitudes, the dominant climate driver is Shum. This study is of guiding significance for the ecological restoration and management of the LP, and it can also provide a scientific basis for the improvement of ecosystems and the sustainable management of water resources in the context of global climate change.

A time‐varying meshing stiffness model for gears with mixed elastohydrodynamic lubrication based on load‐sharing

AbstractIn mixed elastohydrodynamic lubrication (EHL), the load distribution between the gear meshing surfaces is shared by the oil film and the asperities of the gear's rough surface. Based on the load‐sharing concept, this paper proposes a time‐varying meshing stiffness (TVMS) model for gears with mixed EHL. The initial step involves the utilization of the Greenwood‐Williamson model to calculate the contact stiffness of surface asperities, while the lubricating film is assessed using a curve‐fitting formula to investigate the influence of gear surface morphology on TVMS. Subsequently, the incorporation of gear fillet foundation deformation and friction enables accurate TVMS determination. The proposed method is employed to examine the meshing stiffness of the gear pair under both dry lubrication and EHL conditions. Comparative analysis reveals favorable agreement between the proposed model and experimental results obtained under dry lubrication, thereby highlighting the superior performance of the proposed approach. Moreover, the time‐varying friction coefficient under EHL is computed, and the impacts of gear surface morphology parameters, temperature, speed, and load on lubrication conditions and TVMS are investigated. The findings presented in this paper contribute significantly to advancements in gear design and performance.

Mechanics and surface characterization of high-speed diamond turning of germanium

Germanium and other brittle single crystal materials can be diamond turned with negative rake angle tools, but to maintain surface integrity parameters are typically chosen conservatively. This work describes experiments performed on (100)Ge crystal samples that support a recent scientific finding: increasing the surface speed in diamond turning of germanium improves surface integrity. Materials are machined on a modern ultraprecision diamond turning machine at constant surface speed and constant feed per revolution keeping both the geometric character and the material flow dynamics constant during machining. Forces are measured in the experiments at cutting speeds ranging from 0.2 m/s to 10 m/s. Surface roughness of the machined surfaces was characterized using coherence scanning interferometry and surface analysis. The key findings of the work are (a) force and specific forces decrease by approximately a factor of 2 over the cutting speed range and (b) surface damage substantively decreases with cutting speed. This is correlated to the behavior of the cutting forces during machining and the chip geometry. The findings indicate that higher material removal rates can be obtained in diamond turning of germanium and that this increase in material remove rates also improves surface integrity.