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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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All sourcesNASA NTRSDOE OSTI
NASA NTRS2008

Computational Analyses in Support of Sub-scale Diffuser Testing for the A-3 Facility: Steady Predictions - Part 1

Simulation technology can play an important role in rocket engine test facility design and development by assessing risks, providing analysis of dynamic pressure and thermal loads, identifying failure modes and predicting anomalous behavior of critical systems. Advanced numerical tools assume greater significance in supporting testing and design of high altitude testing facilities and plume induced testing environments of high thrust engines because of the greater inter-dependence and synergy in the functioning of the different sub-systems. This is especially true for facilities such as the proposed A-3 facility at NASA SSC because of a challenging operating envelope linked to variable throttle conditions at relatively low chamber pressures. Facility designs in this case will require a complex network of diffuser ducts, steam ejector trains, fast operating valves, cooling water systems and flow diverters that need to be characterized for steady state performance. In this paper, we will demonstrate with the use of CFD analyses s advanced capability to evaluate supersonic diffuser and steam ejector performance in a sub-scale A-3 facility at NASA Stennis Space Center (SSC) where extensive testing was performed. Furthermore, the focus in this paper relates to modeling of critical sub-systems and components used in facilities such as the A-3 facility. The work here will address deficiencies in empirical models and current CFD analyses that are used for design of supersonic diffusers/turning vanes/ejectors as well as analyses for confined plumes and venting processes. The primary areas that will be addressed are: (1) supersonic diffuser performance including analyses of thermal loads (2) accurate shock capturing in the diffuser duct; (3) effect of turning duct on the performance of the facility (4) prediction of mass flow rates and performance classification for steam ejectors (5) comparisons with test data from sub-scale diffuser testing and assessment of confidence levels in CFD based flowpath modeling of the facility. The analyses tools used here expand on the multi-element unstructured CFD which has been tailored and validated for impingement dynamics of dry plumes, complex valve/feed systems, and high pressure propellant delivery systems used in engine and component test stands at NASA SSC. The analyses performed in the evaluation of the sub-scale diffuser facility explored several important factors that influence modeling and understanding of facility operation such as (a) importance of modeling the facility with Real Gas approximation, (b) approximating the cluster of steam ejector nozzles as a single annular nozzle, (c) existence of mixed subsonic/supersonic flow downstream of the turning duct, and (d) inadequacy of two-equation turbulence models in predicting the correct pressurization in the turning duct and expansion of the second stage steam ejectors. The procedure used for modeling the facility was as follows: (i) The engine, test cell and first stage ejectors were simulated with an axisymmetric approximation (ii) the turning duct, second stage ejectors and the piping downstream of the second stage ejectors were analyzed with a three-dimensional simulation utilizing a half-plane symmetry approximation. The solution i.e. primitive variables such as pressure, velocity components, temperature and turbulence quantities were passed from the first computational domain and specified as a supersonic boundary condition for the second simulation. (iii) The third domain comprised of the exit diffuser and the region in the vicinity of the facility (primary included to get the correct shock structure at the exit of the facility and entrainment characteristics). The first set of simulations comprising the engine, test cell and first stage ejectors was carried out both as a turbulent real gas calculation as well as a turbulent perfect gas calculation. A comparison for the two cases (Real Turbulent and Perfect gas turbulent) of the Ma Number distribution and temperature distributions are shown in Figures 1 and 2 respectively. The Mach Number distribution shows small yet distinct differences between the two cases such as locations of shocks/shock reflections and a slightly different impingement point on the wall of the diffuser from the expansion at the exit of the nozzle. Similarly the temperature distribution indicates different flow recirculation patterns in the test cell. Both cases capture all the essential flow phenomena such as the shock-boundary layer interaction, plume expansion, expansion of the first stage ejectors, mixing between the engine plume and the first stage ejector flow and pressurization due to the first stage ejectors. The final paper will discuss thermal loads on the walls of the diffuser and cooling mechanisms investigated.

Allgood, Daniel C.↗
NASA NTRS1993

NLS base heating CFD analysis

Concerns raised over possible base heating effects on the National Launch System (NLS) 1.5 stage reference vehicle resulted in the use of CFD as a predictive analysis tool. The objective established was to obtain good engineering solutions to describe the base region flowfields at 10,000 ft and 50,000 ft altitudes. The Rockwell USA CFD code was employed with a zero-equation turbulence model and a four species, 1 step chemical kinetics package. Three solutions were generated for the specified altitudes on coarse and fine grids. CFD results show the base region flowfields to be highly three dimensional in character. At the 10,000 ft altitude, plumes contract soon after exiting the nozzles and do not interact with each other. No mechanism was identified for driving hot gas back into the base region and no significant amounts of hydrogen or water were found in the base region. Consequently, surface temperatures were all near the ambient level. At 50,000 ft, the nozzle exhaust plumes begin to interact, particularly those of the two inboard engines which are closer together. A small amount of hot gas is recirculated between the inboard nozzles near the nozzle exit plane. As a result, base region surface temperatures are slightly elevated, but still remain well within the design guideline of 1000 R.

Ascoli, Edward P.↗
NASA NTRS1993

CITE 3 meteorological highlights

Meteorological highlights from the third NASA Global Tropospheric Experiment Chemical Instrumentation Test and Evaluation (GTE/CITE 3) are presented. During August and September 1989, research flights were conducted from Wallops Island, Virginia, and Natal, Brazil, and included airborne sampling of air masses over adjacent regions of the Atlantic Ocean. Isentropic backward trajectory calculations, wind vector/streamline fields, rawinsonde data, and GOES and METEOSAT satellite imagery are utilized to examine the meteorological conditions for each flight and to determine the transport paths of the sampled air masses. Some aspects of the chemical signatures of the sampled air are also discussed. During the series of flights based at Wallops Island, Virginia, the flow into the experiment area was governed primarily by the position of the North Atlantic subtropical anticyclone. The large-scale tropospheric circulation switched from primarily a marine flow during flights 1-4, to a predominantly offshore mid-latitude continental flow during flights 5-10. During these later flights, the regional influences of large eastern U.S. cities along with vertical mixing by typical summertime convective activity strongly influenced the chemical characteristics of the sampled air. During the series of flights based at Natal, Brazil, the dominant synoptic feature was the South Atlantic subtropical anticyclone which generally transported air across the tropical Atlantic toward eastern Brazil. Pronounced subsidence and a well-defined trade wind inversion often characterized the lower and middle troposphere over the Natal region. Some high-altitude recirculation of air from South America was observed, as was cross-equatorial transport which had come from northern Africa. Biomass burning plumes were observed on segments of all of the flights, the source region being the central and southern savannah regions of Africa.

Shipham, Mark C.↗
NASA NTRS2010

Can the Plasmaspheric Plume Significantly Contribute to Magnetosheath Densities?

Intervals of strong magnetospheric convection electric fields can result in the removal of large portions of the outer plasmasphere and its transport to the vicinity of the magnetopause. Of growing interest is the disposition of that plasma and its possible influence on the processes operating in the regions contributed to by this dense thermal plasma of ionospheric origin. Plasmaspheric plasma may recirculate within the outer magnetosphere through the flanks to become part of the plasmasheet, be entrained on reconnected magnetic field lines drawn anti-sunward over the polar cap, or be lost into the magnetosheath flow and into the solar wind. Of interest here is whether it is reasonable to anticipate that the plume material is sufficient to contribute substantially to magnetosheath densities at the magnetopause where it could influence reconnection between the interplanetary and terrestrial magnetic fields. We present the results of model simulations of plasmaspheric plume and magnetosheath plasmas in the context of several storm-time event periods. Plume and magnetosheath densities are compared as a function of location and storm phase. The short answer is, "yes", but not always and not at all locations. The full answer will be presented.

Gallagher, Dennis↗
NASA NTRS1995

The Thermal Ion Dynamics Experiment and Plasma Source Instrument

The Thermal Ion Dynamics Experiment (TIDE) and the Plasma Source Instrument (PSI) have been developed in response to the requirements of the ISTP Program for three-dimensional (3D) plasma composition measurements capable of tracking the circulation of low-energy (0-500 eV) plasma through the polar magnetosphere. This plasma is composed of penetrating magnetosheath and escaping ionospheric components. It is in part lost to the downstream solar wind and in part recirculated within the magnetosphere, participating in the formation of the diamagnetic hot plasma sheet and ring current plasma populations. Significant obstacles which have previously made this task impossible include the low density and energy of the outflowing ionospheric plasma plume and the positive spacecraft floating potentials which exclude the lowest-energy plasma from detection on ordinary spacecraft. Based on a unique combination of focusing electrostatic ion optics and time of flight detection and mass analysis, TIDE provides the sensitivity (seven apertures of about 1 cm squared effective area each) and angular resolution (6 x 18 degrees) required for this purpose. PSI produces a low energy plasma locally at the POLAR spacecraft that provides the ion current required to balance the photoelectron current, along with a low temperature electron population, regulating the spacecraft potential slightly positive relative to the space plasma. TIDE/PSI will: (a) measure the density and flow fields of the solar and terrestrial plasmas within the high polar cap and magnetospheric lobes; (b) quantify the extent to which ionospheric and solar ions are recirculated within the distant magnetotail neutral sheet or lost to the distant tail and solar wind; (c) investigate the mass-dependent degree energization of these plasmas by measuring their thermodynamic properties; (d) investigate the relative roles of ionosphere and solar wind as sources of plasma to the plasma sheet and ring current.

Moore, T. E.↗
DOE OSTI2020

Impacts on mechanical strength of chemical reactions induced by hydrous supercritical CO2 in Boise Sandstone

Geomechanics experiments were used to assess mechanical alteration of Boise Sandstone promoted by reactions with supercritical carbon dioxide (scCO 2 ) and water vapor. During geologic carbon storage, scCO 2 is injected into subsurface reservoirs, forming buoyant plumes. At brine-plume interfaces, scCO 2 can dissolve into native brines, and water from brines can partition into scCO 2 , forming hydrous scCO 2 . This study investigates the effect of hydrous scCO 2 on the strength of Boise Sandstone. Samples are first exposed to recirculating hydrous scCO 2 for 24 h at 70 °C and 13.8 MPa scCO 2 pressure. Samples are reacted with scCO 2 with added water contents up to 500 mL. After scCO 2 exposure, samples are deformed at room temperature under confining pressures of 3.4, 6.9, and 10.3 MPa. The results demonstrate that hydrous scCO 2 induces chemical reactions in Boise Sandstone, with ions migrating from the solid into the hydrous scCO 2 phase. At the longer time-scales, these reactions could lead to mechanical weakening in the samples; however, on the scale of our experiments, the strength changes are within sample variability. Because the solubility of water in scCO 2 is extremely low (0.008 mol H 2 O per 1 mol CO 2 ), the mineral dissolution of Boise Sandstone was under 0.002 wt.%. Additionally, mineral grains and pore throats in Boise Sandstone are cemented with quartz, which is not susceptible to dissolution at these conditions. Our results indicate that humidity in scCO 2 plumes is unlikely to sustain chemical reactions and induce long term strength changes in quartz cemented sandstones due to resistant mineralogies and low water solubility.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1994

Experimental and numerical study of swept ramp injection into a supersonic flowfield

Time-averaged measurements of pressure, temperature, velocity, and injectant mole fraction are presented using the planar laser-induced iodine fluorescence technique in the complex three-dimensional compressible flowfield around a swept ramp fuel injector. Within the range of thermodynamic conditions present in the test case studied, the technique's accuracy is estimated to be 4% for pressure, temperature, and velocity and 3% for injectant mole fraction. Comparisons with numerical simulations using the SPARK three-dimensional Navier-Stokes computer code with an algebraic turbulence model are made at the centerplane of the flowfield as well as on three crossflow planes downstream of the injector. Calculations and measurements are in good agreement throughout the flowfield, with deviations on the order of 5%; however, in specific regions, such as in the base of the ramp, deviations are larger. A weak asymmetry in the incoming flowfield appears to be amplified by boundary-layer separation occurring when the ramp-generated shock reflects off the tunnel walls. Ramp-generated vortices are weaker in the calculated results due to the effects of numerical viscosity in the vortex cores. This leads to less turning and mixing of the jet plume than observed in the experiments. The rate of decay of the maximum injectant mole fraction with streamwise distance is greater for the present ramp injection scheme than for previously measured transverse injection schemes. In this recirculation region at the base of the injector, laminar calculations show better agreement with the measurements than turbulent calculations.

Donohue, James M.↗
NASA NTRS2022

The Impacts of Freshwater Input and Surface Wind Velocity on the Strength and Extent of a Large High Latitude River Plume

Arctic Ocean physical and biogeochemical properties are strongly influenced by freshwater input from land and through the Bering Strait, where the mean currents transport water northward from the Bering Sea. The Yukon River is one of the largest rivers in North America and the Arctic, contributing large quantities of freshwater and terrigenous material to the coastal ocean in the northern Bering Sea. However, a detailed analysis of the coastal hydrodynamics at the outflow of the river has not been conducted in this remote but regionally important river. A three-dimensional hydrodynamic model was built to represent the lower Yukon River and coastal ocean for the ice-free months in 7 years. On average, a large anticyclonic eddy persisted at the main outflow of the Yukon that recirculates water back toward the coast where the currents converge to form a mean northward transport along the delta. Interannual spatial variance in salinity was relatively small, while there was substantial variance in u and v current velocity. u velocity spatial variance was correlated to the volume of freshwater discharge across years, while v velocity spatial variance was correlated to the N–S wind velocity. During strong wind events, plume structure was substantially altered: southerly winds deepened the plume and enhanced northward transport, while northerly winds shoaled and strengthened the pycnocline, and reversed the flow toward the south. The variability in plume dispersion on short time scales due to wind forcing has implications for where terrigenous material is processed in and settles out of the water column.

river plume↗
NASA NTRS1979

A shock capturing application of the finite element method

The paper is concerned with the development of finite element algorithms for the solution of viscous compressible flow problems with possible embedded shocks and recirculation regions. As a first step, the calculation in Cartesian coordinates of uniform flow on a rectangular region which encounters an embedded oblique shock with known turning angle is considered. A code is developed which is then used for computation of the boattail plume simulator problem in cylindrical coordinates. Oblique shock calculations are performed and the results are compared with a known finite difference solution.

Cooke, C. H.↗
NASA NTRS2019

The Flow of Plasmaspheric Plasma in the Inner Magnetosphere: An Introduction to a Subtopic and the Methodology

The spatial and temporal variation of plasmaspheric mass throughout the inner magnetosphere as a function of changing geomagnetic and solar wind conditions is a consequence of its transport throughout the system. It is proposed that the global measurement of 30.4 -nm EUV emission from plasmaspheric He+ can be used to derive the mass transport pathways, as well as the dynamic conditions and locations of when specific pathways are active. This is to be accomplished using observations obtained by the Extreme Ultraviolet Instrument (EUV) on the Imager for Magnetopause -to-Aurora Global Exploration Mission (IMAGE). Questions to be addressed by this approach include evaluation of whether plasmaspheric transport fully accounts for the plasma lost through erosion a nd plume formation, through inward compression of the plasmapause, or by plasma redistributed back into the ionosphere? Does plasmaspheric erosion begin near 3h MLT, sweeping plasma dawnward and duskward as some report? Can the mass in a persistent plume be accounted for by continued loss from within the body of the plasmasphere or must the ionosphere be an active source? These questions are part of the broader unresolved morphology of the global circulation of plasmaspheric plasma through the magnetosphere to be lost into the solar wind, recirculated, or returned to the ionosphere. An initial demonstrations of the methodology and corresponding results will be presented.

Gallagher, D. L.↗
NASA NTRS1976

Technical challenges of integrating the Space Shuttle

A review is presented of the technology involved in integrating the Space Shuttle system. A powered flight analysis of the Shuttle is presented, touching upon the following areas: ascent profile and abort mode integration, sizing and design, control of load factor by a stage thrust shaping, structural load constraints, flight performance reserve and trajectory design for the orbital flight test. A discussion is presented of aerothermodynamics including aerodynamic and plume heating. Flight control and separation is considered with attention paid to liftoff, ascent to booster staging, elevon load relief, booster tailoff thrust mismatch and gimbal limitations and booster separation. Structural analysis and dynamics is examined, considering: vehicle loads and modes and the pogo effect. Propulsion aspects (hydraulics, the LH2 recirculation system, the antigeyser system, the pressurization system, etc.), ground vibration tests, separation system verification and flight readiness firing are all described.

Martin, A. C.↗
NASA NTRS1992

An iodine hypersonic wind tunnel for the study of nonequilibrium reacting flows

A pilot scale hypersonic wind tunnel operating on pure iodine vapor has been designed and tested. The wind tunnel operates intermittently with a run phase lasting approximately 20 minutes. Successful recirculation of the iodine used during the run phase has been achieved but can be improved. Relevant issues regarding the full scale facility's design and operation, and the use of iodine as a working gas are discussed. Continuous wave laser induced fluorescence was used to monitor number densities within the plume flowfield, while pulsed laser induced fluorescence was used in an initial attempt to measure vibrational energy state population distributions. Preliminary nozzle flow calculations based on finite rate chemistry are presented.

Pham-Van-diep, G. C.↗
NASA NTRS1986

Dual throat thruster test results

Test results are presented for a dual throat thruster burning gaseous oxygen and hydrogen at primary (inner) chamber pressures from 380 to 680 psia. Heat flux profiles were obtained from calorimetric cooling channels in the inner nozzle, outer or secondary chamber and the tip of the inner nozzle. Data were obtained for two nozzle spacings over a chamber pressure ratio (secondary/primary) range of 0.45 to 0.83 with both chambers firing (Mode I). Fluxes near the end of the inner nozzle were significantly higher than in Mode II when only the inner chamber was fired, due to flow separation and recirculation caused by the back pressure imposed by the secondary chamber. As the pressure ratio increased, these heat fluxes increased and the region of high heat flux relative to Mode II extended farther upstream. The use of a gaseous hydrogen bleed flow in the secondary chamber to control heat fluxes in the primary plume attachment region was investigated in Mode II testing. A bleed flow of less than two percent of the primary chamber flow was required.

Ewen, R. L.↗
NASA NTRS1986

Dual-throat thruster thermal model

The dual-throat engine is one of the dual nozzle engine concepts studied for advanced space transportation applications. It provides a thrust change and an in-flight area ratio change through the use of two concentric combustors with their throats arranged in series. Test results are presented for a dual throat thruster burning gaseous oxygen and hydrogen at primary (inner) chamber pressures from 380 to 680 psia. Heat flux profiles were obtained from calorimetric cooling channels in the inner nozzle, outer or secondary chamber and the tip of the inner nozzle. Data were obtained for two nozzle spacings over a chamber pressure ratio (secondary/primary) range of 0.45 to 0.83 with both chambers firing (Mode I). Fluxes near the end of the inner nozzle were significantly higher than in Mode II when only the inner chamber was fired, due to the flow separation and recirculation caused by the back pressure imposed by the secondary chamber. As the pressure ratio increased, these heat fluxes increased and the region of high heat flux relative to Mode II extended farther upstream. The use of the gaseous hydrogen bleed flow in the secondary chamber to control heat fluxes in the primary plume attachment region was investigated in Mode II testing. A thermal model of a dual throat thruster was developed and upgraded using the experimental data.

Ewen, R. L.↗
NASA NTRS2015

Quantification of Plume-Soil Interaction and Excavation Due to the Sky Crane Descent Stage

The quantification of the particulate erosion that occurs as a result of a rocket exhaust plume impinging on soil during extraterrestrial landings is critical for future robotic and human lander mission design. The aerodynamic environment that results from the reflected plumes results in dust lifting, site alteration and saltation, all of which create a potentially erosive and contaminant heavy environment for the lander vehicle and any surrounding structures. The Mars Science Lab (MSL), weighing nearly one metric ton, required higher levels of thrust from its retro propulsive systems and an entirely new descent system to minimize these effects. In this work we seek to quantify plume soil interaction and its resultant soil erosion caused by the MSL's Sky Crane descent stage engines by performing three dimensional digital terrain and elevation mapping of the Curiosity rover's landing site. Analysis of plume soil interaction altitude and time was performed by detailed examination of the Mars Descent Imager (MARDI) still frames and reconstructed inertial measurement unit (IMU) sensor data. Results show initial plume soil interaction from the Sky Crane's eight engines began at ground elevations greater than 60 meters and more than 25 seconds before the rovers' touchdown event. During this time, viscous shear erosion (VSE) was dominant typically resulting in dusting of the surface with flow propagating nearly parallel to the surface. As the vehicle descended and decreased to four powered engines plume-plume and plume soil interaction increased the overall erosion rate at the surface. Visibility was greatly reduced at a height of roughly 20 meters above the surface and fell to zero ground visibility shortly after. The deployment phase of the Sky Crane descent stage hovering at nearly six meters above the surface showed the greatest amount of erosion with several large particles of soil being kicked up, recirculated, and impacting the bottom of the rover chassis. Image data obtained from MSL's navigation camera (NAVCAM) pairs on Sols 002, 003, and 016 were used to virtually recreate local surface topography and features around the rover by means of stereoscopic depth mapping. Images taken simultaneously by the left and right navigation cameras located on the rover's mast assembly spaced 42 centimeters were used to generate a three dimensional depth map from flat, two dimensional images of the same feature at slightly different angles. Image calibration with physical hardware on the rover and known terrain features were used to provide scaling information that accurately sizes features and regions of interest within the images. Digital terrain mapping analysis performed in this work describe the crater geometry (shape, radius, and depth), eroded volume, volumetric erosion rate, and estimated mass erosion rate of the Hepburn, Sleepy Dragon, Burnside, and Goulburn craters. Crater depths ranged from five to ten centimeters deep influencing an area as wide as two meters in some cases. The craters formed were highly asymmetrical and generally oblong primarily due to the underlying bedrock formations underneath the surface. Comparison with ground tests performed at the NASA AMES Planetary Aeolian Laboratory (PAL) by Mehta showed good agreement with volumetric erosion rates and crater sizes of large particle soil simulants, providing validation to Earth based ground tests of Martian regolith.

Vizcaino, Jeffrey↗
NASA NTRS1978

Specific spacecraft evaluation: Special report

Charged and neutral particle transport from an 8 cm mercury ion thruster to the surfaces of the P 80-1 spacecraft and to the Teal Ruby sensor and the ECOM-501 sensor of that spacecraft were investigated. Laboratory measurements and analyses were used to examine line-of-sight and nonline-of sight particle transport modes. The recirculation of Hg(+) ions in the magnetic field of the earth was analyzed for spacecraft velocity and Earth magnetic field vector configurations which are expected to occur in near Earth, circular, high inclination orbits. For these magnetic field and orbit conditions and for expected ion release distribution functions, in both angles and energies, the recirculation/re-interception of ions on spacecraft surfaces was evaluated. The refraction of weakly energetic ions in the electric fields of the thruster plasma plume and in the electric fields between this plasma plume and the material boundaries of the thruster, the thruster sputter shield, and the various spacecraft surfaces were examined. The neutral particle transport modes of interest were identified as sputtered metal atoms from the thruster beam shield. Results, conclusions, and future considerations are presented.

Sellen, J. M., Jr.↗
NASA NTRS1978

SSV Generic OFT first stage ascent base convective heating environments

Space Shuttle Vehicle (SSV) base convective heating environments during the recirculated flow time segment of first stage ascent were determined for the Generic OFT trajectory and performance conditions. These environments are presented in the attachments as cold wall convective heat transfer coefficients for individual or groups of design points for all affected SSV base surfaces. Two gas recovery temperatures applicable to upper and lower base region surfaces are also included. The environments were based upon magnitudes and trends from analysis of data taken during Base Heating Tests IH-39, IH-75, and IH-83. The plume heating trajectory and performance data were supplied by Rockwell International for both the OFT-1 Generic Mission A and Mission C.

Bender, R. L., Jr.↗
NASA NTRS1980

Numerical solutions of the Navier-Stokes equations for transonic afterbody flows

The time dependent Navier-Stokes equations in mass averaged variables are solved for transonic flow over axisymmetric boattail plume simulator configurations. Numerical solution of these equations is accomplished with the unsplit explict finite difference algorithm of MacCormack. A grid subcycling procedure and computer code vectorization are used to improve computational efficiency. The two layer algebraic turbulence models of Cebeci-Smith and Baldwin-Lomax are employed for investigating turbulence closure. Two relaxation models based on these baseline models are also considered. Results in the form of surface pressure distribution for three different circular arc boattails at two free stream Mach numbers are compared with experimental data. The pressures in the recirculating flow region for all separated cases are poorly predicted with the baseline turbulence models. Significant improvements in the predictions are usually obtained by using the relaxation models.

Swanson, R. C., Jr.↗