Sahu, Jabaraj
Overview
Works:  66 works in 69 publications in 1 language and 1,328 library holdings 

Roles:  Author 
Classifications:  TL574.T8, 
Publication Timeline
.
Most widely held works by
Jabaraj Sahu
NavierStokes computational study of axisymmetric transonic turbulent flows with a twoequation model of turbulence by
Jabaraj Sahu(
)
1 edition published in 1984 in English and held by 3 WorldCat member libraries worldwide
1 edition published in 1984 in English and held by 3 WorldCat member libraries worldwide
Numerical Computation of Base Flow for a Projectile at Transonic Speeds(
Book
)
1 edition published in 1983 in English and held by 1 WorldCat member library worldwide
The generalizedAxisymmetric ThinLayer NavierStokes computational technique has been modified for projectile base flow analysis. The resulting new numerical capability is used to compute the entire projectile flow field including the recirculatory base flow. Computed results show the qualitative and quantitative details of the overall base flow structure. Base drag is computed for a secantogivecylinder projectile at an angle of attack of zero and compared with available experimental data and a semiempirical analysis. Results are also presented which show pressure drag, skin friction drag and total aerodynamic drag for Mach No. .9 <M <1.2. (Author)
1 edition published in 1983 in English and held by 1 WorldCat member library worldwide
The generalizedAxisymmetric ThinLayer NavierStokes computational technique has been modified for projectile base flow analysis. The resulting new numerical capability is used to compute the entire projectile flow field including the recirculatory base flow. Computed results show the qualitative and quantitative details of the overall base flow structure. Base drag is computed for a secantogivecylinder projectile at an angle of attack of zero and compared with available experimental data and a semiempirical analysis. Results are also presented which show pressure drag, skin friction drag and total aerodynamic drag for Mach No. .9 <M <1.2. (Author)
Computational Study of the M825 Projectile with Standard and Dome Bases(
Book
)
1 edition published in 1988 in English and held by 1 WorldCat member library worldwide
Test firings of a 155mm artillery projectile have shown that its flight performance is affected by small changes in the base cavity configurations. A clear understanding of why these changes affect the flight behavior does not exist. A computational study has been made for the two base cavity configurations flight tested. Flowfield computations have been performed at 0.8 <Mach <1.5 using a NavierStokes base flow code. The aerodynamic drag components have been computed and the total drag determined. Computed results show differences in qualitative features of the recirculatory flow in the base region. The code predicts small differences in drag between the base cavity configurations
1 edition published in 1988 in English and held by 1 WorldCat member library worldwide
Test firings of a 155mm artillery projectile have shown that its flight performance is affected by small changes in the base cavity configurations. A clear understanding of why these changes affect the flight behavior does not exist. A computational study has been made for the two base cavity configurations flight tested. Flowfield computations have been performed at 0.8 <Mach <1.5 using a NavierStokes base flow code. The aerodynamic drag components have been computed and the total drag determined. Computed results show differences in qualitative features of the recirculatory flow in the base region. The code predicts small differences in drag between the base cavity configurations
Supersonic Flow Over Cylindrical Afterbodies with Base Bleed(
Book
)
1 edition published in 1986 in English and held by 1 WorldCat member library worldwide
Computations of supersonic flow over two cylindrical afterbodies have been made using a thinlayer NavierStokes base flow code. The capability to compute the base flow with base bleed at supersonic speeds has been developed and used to show the effect of mass injection on the base pressure or base drag. Solutions have been obtained for a projectile and a missile configuration having cylindrical afterbodies. Numerical results show the effect of base bleed on the near wake flow field. The rise in base pressure or reduction in base drag has been clearly predicted for various mass injection rates and comparison with experimental data shows generally good agreement
1 edition published in 1986 in English and held by 1 WorldCat member library worldwide
Computations of supersonic flow over two cylindrical afterbodies have been made using a thinlayer NavierStokes base flow code. The capability to compute the base flow with base bleed at supersonic speeds has been developed and used to show the effect of mass injection on the base pressure or base drag. Solutions have been obtained for a projectile and a missile configuration having cylindrical afterbodies. Numerical results show the effect of base bleed on the near wake flow field. The rise in base pressure or reduction in base drag has been clearly predicted for various mass injection rates and comparison with experimental data shows generally good agreement
Drag Predictions for Projectiles at Transonic and Supersonic Speeds(
Book
)
1 edition published in 1986 in English and held by 1 WorldCat member library worldwide
The breakdown of the total drag into its individual components (pressure drag, viscous drag, and base drag) is important in the preliminary design stage of shell. Design codes are available to predict the individual drag components and thus, the total drag. Typically, the total drag predicted by these design codes agrees well with the total drag measured from flight tests. But, how well do these codes predict the individual drag components? Experimental verification of the prediction of the drag components is an extremely difficult task. Thus a NavierStokes computational procedure is used in this report to predict the individual drag components and test the accuracy of the predictions of the design codes. A thinlayer NavierStokes code has been used to compute the entire flow field over projectiles including the base region. Numerical calculations have been made for various Mach numbers in the transonic and supersonic regimes. Pressure drag, skin friction drag, base drag and thus, the total drag are obtained from the computed results. Comparison of drag has been made with available experimental data and also with predictions from design codes employing semiempirical techniques
1 edition published in 1986 in English and held by 1 WorldCat member library worldwide
The breakdown of the total drag into its individual components (pressure drag, viscous drag, and base drag) is important in the preliminary design stage of shell. Design codes are available to predict the individual drag components and thus, the total drag. Typically, the total drag predicted by these design codes agrees well with the total drag measured from flight tests. But, how well do these codes predict the individual drag components? Experimental verification of the prediction of the drag components is an extremely difficult task. Thus a NavierStokes computational procedure is used in this report to predict the individual drag components and test the accuracy of the predictions of the design codes. A thinlayer NavierStokes code has been used to compute the entire flow field over projectiles including the base region. Numerical calculations have been made for various Mach numbers in the transonic and supersonic regimes. Pressure drag, skin friction drag, base drag and thus, the total drag are obtained from the computed results. Comparison of drag has been made with available experimental data and also with predictions from design codes employing semiempirical techniques
Computational Fluid Dynamics Modeling of Multibody Missile Aerodynamic Interference(
Book
)
2 editions published in 1998 in English and held by 1 WorldCat member library worldwide
Computational fluid dynamics (CFD) calculations have been performed for a multibody system consisting of a main missile and a number of submunitions. Numerical flow field computations have been made for various orientations and locations of submunitions using an unsteady, zonal NavierStokes code and the chimera composite grid discretization technique at transonic speeds and zero degree angle of attack. Both steady state and unsteady numerical results have been obtained and compared for two submunitions and a missile system. Computed results show the details of the expected flow field features, including the shock interactions. Computed results are compared with limited experimental data obtained for the same configuration and conditions and are generally found to be in good agreement with the data. Comparison of the unsteady and steady state results shows an appreciable change in the aerodynamic forces and moments
2 editions published in 1998 in English and held by 1 WorldCat member library worldwide
Computational fluid dynamics (CFD) calculations have been performed for a multibody system consisting of a main missile and a number of submunitions. Numerical flow field computations have been made for various orientations and locations of submunitions using an unsteady, zonal NavierStokes code and the chimera composite grid discretization technique at transonic speeds and zero degree angle of attack. Both steady state and unsteady numerical results have been obtained and compared for two submunitions and a missile system. Computed results show the details of the expected flow field features, including the shock interactions. Computed results are compared with limited experimental data obtained for the same configuration and conditions and are generally found to be in good agreement with the data. Comparison of the unsteady and steady state results shows an appreciable change in the aerodynamic forces and moments
Numerical Flow Field Calculations for a Missile Configuration at M = .6(
Book
)
1 edition published in 1986 in English and held by 1 WorldCat member library worldwide
Large separated flow region can seriously degrade the effectiveness of fins or any other control surface located in that region. A knowledge of the expected flow field can thus be very important in the initial design phase of a missile or projectile. The Aerodynamics Technology Branch of the US Army Missile Laboratory has requested numerical flow field data for a new missile design. Numerical computations have been made for the requested missile configuration at M = 0.6 and the results of these computations are presented in this report. A thinlayer NavierStokes base flow code has been used to compute the flow field for a full missile configuration including the base region. Numerical calculations have been made for both laminar and turbulent flow conditions. Details of the computed flow field are presented in the form of plots showing surface pressure distribution, velocity vectors, stream function and Mach number contours, particle paths and boundary layer parameters. (Author)
1 edition published in 1986 in English and held by 1 WorldCat member library worldwide
Large separated flow region can seriously degrade the effectiveness of fins or any other control surface located in that region. A knowledge of the expected flow field can thus be very important in the initial design phase of a missile or projectile. The Aerodynamics Technology Branch of the US Army Missile Laboratory has requested numerical flow field data for a new missile design. Numerical computations have been made for the requested missile configuration at M = 0.6 and the results of these computations are presented in this report. A thinlayer NavierStokes base flow code has been used to compute the flow field for a full missile configuration including the base region. Numerical calculations have been made for both laminar and turbulent flow conditions. Details of the computed flow field are presented in the form of plots showing surface pressure distribution, velocity vectors, stream function and Mach number contours, particle paths and boundary layer parameters. (Author)
Comparison of Numerical Flow Field Predictions for Army Airdrop Systems(
Book
)
2 editions published in 1999 in English and held by 1 WorldCat member library worldwide
A computational study has been performed to determine the aerodynamics of Army airdrop systems using computational fluid dynamics (CFD). The validation of flow field predictions from CFD software packages for airdrop systems is difficult because comprehensive experimentally obtained data are lacking. This is especially true for real systems because obtaining desired flow field data during a test is not practical or possible with available technologies. This report examines the results of predictions from two separate CFD codes for the same airdrop systems as an initial step toward validating high performance computing software for modeling airdrop systems. Numerical results have been obtained on two airdrop systems used by the U.S. Army: the T10 personnel system (no payload) and the G12 cargo system with and without a payload. The two software packages used for the comparisons are a CFD code that employs a stabilized semidiscrete finite element formulation of the incompressible NavierStokes equations and CFD++, a commercially available code. For this numerical experiment, computed unsteady flow fields were obtained with the same unstructured mesh, and predicted flow fields were compared. Similarities and discrepancies in the comparisons are highlighted, and conclusions are drawn from these results
2 editions published in 1999 in English and held by 1 WorldCat member library worldwide
A computational study has been performed to determine the aerodynamics of Army airdrop systems using computational fluid dynamics (CFD). The validation of flow field predictions from CFD software packages for airdrop systems is difficult because comprehensive experimentally obtained data are lacking. This is especially true for real systems because obtaining desired flow field data during a test is not practical or possible with available technologies. This report examines the results of predictions from two separate CFD codes for the same airdrop systems as an initial step toward validating high performance computing software for modeling airdrop systems. Numerical results have been obtained on two airdrop systems used by the U.S. Army: the T10 personnel system (no payload) and the G12 cargo system with and without a payload. The two software packages used for the comparisons are a CFD code that employs a stabilized semidiscrete finite element formulation of the incompressible NavierStokes equations and CFD++, a commercially available code. For this numerical experiment, computed unsteady flow fields were obtained with the same unstructured mesh, and predicted flow fields were compared. Similarities and discrepancies in the comparisons are highlighted, and conclusions are drawn from these results
Computational Modeling of a Segmented Projectile(
Book
)
2 editions published in 1999 in English and held by 1 WorldCat member library worldwide
This report describes the application of the chimera numerical technique to a multibody segmented projectile configuration system of interest to the U.S. Army. Computations were performed at a supersonic speed on this configuration which consists of an ogive cylinder projectile with a peg shaped trailing segment. The computed results show the qualitative features of the wake flow field for the projectile with the segment in three different positions: centered, offset, and angled. The segment in the offset position has a strong effect on the flow field in the aft region of the projectile, thus affecting the aerodynamic coefficients of the projectile. The force and moment coefficients of the segment are also significantly affected by the orientation of the segment
2 editions published in 1999 in English and held by 1 WorldCat member library worldwide
This report describes the application of the chimera numerical technique to a multibody segmented projectile configuration system of interest to the U.S. Army. Computations were performed at a supersonic speed on this configuration which consists of an ogive cylinder projectile with a peg shaped trailing segment. The computed results show the qualitative features of the wake flow field for the projectile with the segment in three different positions: centered, offset, and angled. The segment in the offset position has a strong effect on the flow field in the aft region of the projectile, thus affecting the aerodynamic coefficients of the projectile. The force and moment coefficients of the segment are also significantly affected by the orientation of the segment
Application of computational fluid dynamics to a monoplane fixedwing missile with elliptic cross sections by
Karen R Heavey(
)
1 edition published in 2005 in English and held by 0 WorldCat member libraries worldwide
1 edition published in 2005 in English and held by 0 WorldCat member libraries worldwide
Comparison of numerical flow field predictions for army airdrop systems(
)
1 edition published in 1999 in English and held by 0 WorldCat member libraries worldwide
1 edition published in 1999 in English and held by 0 WorldCat member libraries worldwide
TimeAccurate Calculations of FreeFlight Aerodynamics of Maneuvering Projectiles(
)
1 edition published in 2007 in English and held by 0 WorldCat member libraries worldwide
This paper describes a multidisciplinary computational study undertaken to model the flight trajectories and the freeflight aerodynamics of finned projectiles both with and without control maneuvers. Advanced computational capabilities both in computational fluid dynamics (CFD) and rigid body dynamics (RBD) have been successfully fully coupled on high performance computing (HPC) platforms for "Virtual FlyOuts" of munitions similar to actual free flight tests in the aerodynamic experimental facilities. Timeaccurate NavierStokes computations have been performed to compute the unsteady aerodynamics associated with the free flight of a finned projectile at a supersonic speed using an advanced scalable unstructured flow solver on a highly parallel Linux Cluster. Some results relating to the portability and the performance of the flow solver on the Linux clusters are also addressed Computed positions and orientations of the projectile along the flight trajectory have been compared with actual data measured from free flight tests and are found to be generally in good agreement. Computed results obtained for another complex finned configuration with canardcontrol pitchup maneuver in a virtual flyout show the potential of these techniques for providing the actual timedependent response of the flight vehicle and the resulting unsteady aerodynamics for maneuvering projectiles
1 edition published in 2007 in English and held by 0 WorldCat member libraries worldwide
This paper describes a multidisciplinary computational study undertaken to model the flight trajectories and the freeflight aerodynamics of finned projectiles both with and without control maneuvers. Advanced computational capabilities both in computational fluid dynamics (CFD) and rigid body dynamics (RBD) have been successfully fully coupled on high performance computing (HPC) platforms for "Virtual FlyOuts" of munitions similar to actual free flight tests in the aerodynamic experimental facilities. Timeaccurate NavierStokes computations have been performed to compute the unsteady aerodynamics associated with the free flight of a finned projectile at a supersonic speed using an advanced scalable unstructured flow solver on a highly parallel Linux Cluster. Some results relating to the portability and the performance of the flow solver on the Linux clusters are also addressed Computed positions and orientations of the projectile along the flight trajectory have been compared with actual data measured from free flight tests and are found to be generally in good agreement. Computed results obtained for another complex finned configuration with canardcontrol pitchup maneuver in a virtual flyout show the potential of these techniques for providing the actual timedependent response of the flight vehicle and the resulting unsteady aerodynamics for maneuvering projectiles
Timeaccurate computations of freeflight aerodynamics of a spinning projectile with and without flow control by
Jabaraj Sahu(
)
1 edition published in 2006 in English and held by 0 WorldCat member libraries worldwide
1 edition published in 2006 in English and held by 0 WorldCat member libraries worldwide
Computational fluid dynamics modeling of submunition separation from missile by
Harris L Edge(
)
1 edition published in 1999 in English and held by 0 WorldCat member libraries worldwide
1 edition published in 1999 in English and held by 0 WorldCat member libraries worldwide
Numerical computations of supersonic flow over a square crosssection missile by Sidra I Silton(
)
1 edition published in 2005 in English and held by 0 WorldCat member libraries worldwide
This report describes a computational study undertaken to determine the aerodynamics of a nonaxisymmetric missile with a square cross section. Numerical solutions have been obtained at supersonic speeds for various roll orientations and angles of attack using a twoequation Reynoldsaveraged NavierStokes turbulence model. Numerical results show the qualitative features (vortices and crossflow separation regions) of the flow field at various stream wise positions along the missile configurations. Aerodynamic coefficients have been obtained from the computed solutions and found to match well with the available experimental data for these configurations. These numerical results show the ability of computational fluid dynamics techniques to accurately predict the aerodynamics of nonaxisymmetric missiles with a square cross section
1 edition published in 2005 in English and held by 0 WorldCat member libraries worldwide
This report describes a computational study undertaken to determine the aerodynamics of a nonaxisymmetric missile with a square cross section. Numerical solutions have been obtained at supersonic speeds for various roll orientations and angles of attack using a twoequation Reynoldsaveraged NavierStokes turbulence model. Numerical results show the qualitative features (vortices and crossflow separation regions) of the flow field at various stream wise positions along the missile configurations. Aerodynamic coefficients have been obtained from the computed solutions and found to match well with the available experimental data for these configurations. These numerical results show the ability of computational fluid dynamics techniques to accurately predict the aerodynamics of nonaxisymmetric missiles with a square cross section
Timeaccurate numerical prediction of free flight aerodynamics of a finned projectile by
Jabaraj Sahu(
)
1 edition published in 2005 in English and held by 0 WorldCat member libraries worldwide
This report describes a new multidisciplinary computational study undertaken to compute the flight trajectories and to simultaneously predict the unsteady free flight aerodynamics of a finned projectile configuration. Actual flight trajectories are computed by an advanced coupled computational fluid dynamics (CFD)rigid body dynamics technique. An advanced timeaccurate NavierStokes computational technique has been used in CFD to compute the unsteady aerodynamics associated with the free flight of the finned projectile at supersonic speeds. Computed positions and orientations of the projectile have been compared with actual data measured from free flight tests and are found to be generally in good agreement. Predicted aerodynamics forces and moments also compare well with the forces and moments used in the sixdegreeof freedom fits of the results of the same tests. Unsteady numerical results obtained from the coupled method show the aerodynamic forces and moments and the flight path of the projectile
1 edition published in 2005 in English and held by 0 WorldCat member libraries worldwide
This report describes a new multidisciplinary computational study undertaken to compute the flight trajectories and to simultaneously predict the unsteady free flight aerodynamics of a finned projectile configuration. Actual flight trajectories are computed by an advanced coupled computational fluid dynamics (CFD)rigid body dynamics technique. An advanced timeaccurate NavierStokes computational technique has been used in CFD to compute the unsteady aerodynamics associated with the free flight of the finned projectile at supersonic speeds. Computed positions and orientations of the projectile have been compared with actual data measured from free flight tests and are found to be generally in good agreement. Predicted aerodynamics forces and moments also compare well with the forces and moments used in the sixdegreeof freedom fits of the results of the same tests. Unsteady numerical results obtained from the coupled method show the aerodynamic forces and moments and the flight path of the projectile
Unsteady numerical simulations of subsonic llow over a projectile with jet interaction by
Jabaraj Sahu(
)
1 edition published in 2003 in English and held by 0 WorldCat member libraries worldwide
1 edition published in 2003 in English and held by 0 WorldCat member libraries worldwide
Computational Fluid Dynamic (CFD) Analysis of a Generic Missile With Grid Fins(
)
1 edition published in 2000 in English and held by 0 WorldCat member libraries worldwide
This report presents the results of a study demonstrating an approach for using viscous computational fluid dynamic simulations to calculate the flow field and aerodynamic coefficients for a missile with grid fin. A grid fin is an unconventional lifting and control surface that consists of an outer frame supporting an inner grid of intersecting planar surfaces of small chord. The calculations were made at a Mach number of 2.5 and several angles of attack for a missile without fins, with planar fms, and with grid fins. The results were validated by comparing the computed aerodynamic coefficients for the missile and individual grid fins against wind tunnel measurement data. Very good agreement with the measured data was observed for all configurations investigated. For the grid fin case, the aerodynamic coefficients were within 2.86.5% of the wind tunnel data. The normal force coefficients on the individual grid fins were within 11% of the test data. The simulations were also successful in calculating the flow structure around the fin in the separatedflow region at the higher angles of attack. This was evident in the successful calculation of the nonlinear behavior for that fin, which showed negative normal force at the higher angles of attack. The effective angle of attack is negative on either part of or all of the top grid fin for the higher angles of attack
1 edition published in 2000 in English and held by 0 WorldCat member libraries worldwide
This report presents the results of a study demonstrating an approach for using viscous computational fluid dynamic simulations to calculate the flow field and aerodynamic coefficients for a missile with grid fin. A grid fin is an unconventional lifting and control surface that consists of an outer frame supporting an inner grid of intersecting planar surfaces of small chord. The calculations were made at a Mach number of 2.5 and several angles of attack for a missile without fins, with planar fms, and with grid fins. The results were validated by comparing the computed aerodynamic coefficients for the missile and individual grid fins against wind tunnel measurement data. Very good agreement with the measured data was observed for all configurations investigated. For the grid fin case, the aerodynamic coefficients were within 2.86.5% of the wind tunnel data. The normal force coefficients on the individual grid fins were within 11% of the test data. The simulations were also successful in calculating the flow structure around the fin in the separatedflow region at the higher angles of attack. This was evident in the successful calculation of the nonlinear behavior for that fin, which showed negative normal force at the higher angles of attack. The effective angle of attack is negative on either part of or all of the top grid fin for the higher angles of attack
Numerical simulations of supersonic flow over an elliptic projectile with jet interaction by
Jabaraj Sahu(
)
1 edition published in 2003 in English and held by 0 WorldCat member libraries worldwide
1 edition published in 2003 in English and held by 0 WorldCat member libraries worldwide
Timeaccurate simulations of synthetic jetbased flow control for an axisymmetric spinning body by
Jabaraj Sahu(
)
1 edition published in 2004 in English and held by 0 WorldCat member libraries worldwide
This report describes a computational study undertaken to consider the aerodynamic effect of synthetic jets as a means of providing the control authority needed to maneuver a projectile at a low subsonic speed. A timeaccurate NavierStokes computational technique has been used to obtain numerical solutions for the unsteady jetinteraction flow field for a spinning projectile at a subsonic speed, Mach 0.24, and angle of attack, 0 degree. Numerical solutions have been obtained by Reynoldsaveraged NavierStokes (RANS) and hybrid RANSlargeeddy simulation turbulence models. Unsteady numerical results show the effect of the jet on the flow field and the aerodynamic coefficients, particularly the lift force. These numerical results are being used to assess if synthetic jets can be used to provide the control authority needed for maneuvering munitions to hit the targets with precision
1 edition published in 2004 in English and held by 0 WorldCat member libraries worldwide
This report describes a computational study undertaken to consider the aerodynamic effect of synthetic jets as a means of providing the control authority needed to maneuver a projectile at a low subsonic speed. A timeaccurate NavierStokes computational technique has been used to obtain numerical solutions for the unsteady jetinteraction flow field for a spinning projectile at a subsonic speed, Mach 0.24, and angle of attack, 0 degree. Numerical solutions have been obtained by Reynoldsaveraged NavierStokes (RANS) and hybrid RANSlargeeddy simulation turbulence models. Unsteady numerical results show the effect of the jet on the flow field and the aerodynamic coefficients, particularly the lift force. These numerical results are being used to assess if synthetic jets can be used to provide the control authority needed for maneuvering munitions to hit the targets with precision
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Related Identities
 U.S. Army Research Laboratory
 Heavey, Karen R. Author
 Edge, Harris L. Author
 Silton, Sidra I. Author
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 Heavey, Karen
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