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Gregory S Jones

Publications and source records attributed to Gregory S Jones.

7 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2020

Artificial Thickening of a Transonic Boundary Layer in the Presence of a Pressure Gradient Associated with a Boundary Layer Ingestion Concept

Boundary layer ingestion is an aeropropulsive concept associated with a propulsion airframe integration technique that integrates viscous aerodynamics into a propulsion system to achieve more efficient flight. The effectiveness of this concept is heavily dependent on how much of the boundary layer is being ingested into the propulsor. Scaling this concept for transonic wind tunnel testing is often plagued with blockage issues and requires a modification to the model dimensions such as fuselage length and diameter and wingspan. To simulate the boundary layer for these modified models requires a manipulation of the boundary layer height to achieve the appropriate ratio of boundary layer to propulsor inlet diameter or height. This paper will focus on 15 different transonic boundary layer manipulators to achieve varying turbulent boundary layer heights for a representative single-aisle transport utilizing Boundary Layer Ingestion.

Gregory S Jones↗
NASA NTRS2017

A Sweeping Jet Application on a High Reynolds Number Semispan Supercritical Wing Configuration

The FAST-MAC circulation control model was modified to test an array of unsteady sweeping-jet actuators at realistic flight Reynolds numbers in the National Transonic Facility at the NASA Langley Research Center. Two types of sweeping jet actuators were fabricated using rapid prototype techniques, and directed over a 15% chord simple-hinged flap. The model was configured for low-speed high-lift testing with flap deflections of 30° and 60°, and a transonic cruise configuration with a 0° flap deflection. For the 30° flap high-lift configuration, the sweeping jets achieved comparable lift performance in the separation control regime, while reducing the mass flow by 54% as compared to steady blowing. However, the sweeping jets were not effective for the 60° flap. For the transonic cruise configuration, the sweeping jets reduced the drag by 3.3% at an off design condition. The drag reduction for the design lift coefficient for the sweeping jets provided only half the drag reduction shown for the steady blowing case (6.5%), but accomplished this with a 74% reduction in mass flow.

Gregory S Jones↗
NASA NTRSDate not supplied

Model Preparation Areas for Propulsion Airframe Integration Testing at NASA Langley Research Center

Currently there are three major NASA Langley facilities that perform PAI testing. These include the National Transonic Facility, the 14’x22’ Low Speed Wind tunnel, and the Unitary Plan Wind Tunnel. While each of these facilities have their own model preparation areas, the model preparation area located at the NTF complex that focuses on blowing systems with high mass flow requirements support all of the LaRC facilities. The application of a Propulsion Airframe Integration requires special attention to the air delivery system interaction with the model. These interactions typically focus on the tares across the balance associated with inlet and nozzle performance which are related to the mass flow through the system and the efficiency of the inlet and nozzle geometries. While this paper does not characterize any specific propulsion system, it does focus on the mass flow and pressures requirement needed for pretesting such systems prior to wind tunnel installation. Weight flow boundaries for the air delivery system were identified to range from 0.1 to 20 lbm/sec.

Model Preparation Area↗
NASA NTRSDate not supplied

Model Preparation Areas for Propulsion Airframe Integration Testing at the NASA Langley Research Center

Currently, there are three major NASA Langley facilities that perform Propulsion Airframe Integration (PAI) testing. These include the National Transonic Facility (NTF), the 14- by 22-Foot Subsonic Tunnel, and the 4-Foot Supersonic Unitary Plan Wind Tunnel. While each of these facilities have their respective model preparation areas, one model preparation area, located at the NTF complex, focuses on high mass flow blowing systems in support of other Langley Research Center facilities. The application of PAI requires special attention to the air delivery system interaction with the model. These interactions focus on the tares across the force and moment balance. The interactions are a result of the mass flow and pressure of the air through the system and the efficiency of the inlet and nozzle geometries. While this paper does not characterize any specific propulsion system, it does focus on the mass flow and pressure requirements for risk-reduction planning of such systems prior to installation in a designated wind tunnel. An example of model and nozzle sizing will be presented for the Tail Cone Thruster (TCT) variant of the Common Research Model (CRM).

PAI↗
NASA NTRSDate not supplied

Self-Aligned Focusing Schlieren at the 0.3-M Transonic Cryogenic Tunnel and the National Transonic Facility

The implementation of a self-aligned focusing schlieren (SAFS) system at two cryogenic wind tunnels at NASA Langley Research Center is discussed. Risk-reduction testing of the SAFS system was first performed at the 0.3-M Transonic Cryogenic Tunnel to evaluate the system’s operation in a small-scale characteristic cryogenic facility. Testing was conducted with three models: a three-quarter span 25.4-mm-diameter cylinder, a semi-span 65A006 tapered unswept airfoil, and a full-span SC(3)-0712 airfoil. Testing with the cylinder and semi-span airfoil revealed a highly dynamic shock environment, whereas the shock on the full-span airfoil was stationary, solidifying the usage of this model for a pre-/post-shock particle tracking velocimetry measurement. Temperature-induced polarization-altering window stresses were encountered during low-temperature testing and were mitigated using a “non-ideal” quartz/quartz Rochon prism that had largely been neglected since the SAFS system’s first introduction in favor of the more favorable “ideal” glass/quartz Rochon prism. The size of the SAFS system was then decreased in order to fit inside an environmentally controlled camera can enclosure at the National Transonic Facility (NTF) for testing of a sting-mounted aircraft model. The SAFS system was demonstrated to be effective at filtering out the large density gradient flow in the0.3-M plenum, and the thick, high density turbulent boundary layers on the wind tunnel walls at the NTF. Results of the testing campaigns and improvements to future systems are discussed.

Joshua M Weisberger↗