Simulation study of helicopter ship landing procedures incoporating measured flow data

The aim of this article is to investigate the use of inverse simulation to help identify those regions of a ship's flight deck which provide the safest locations for landing a rotorcraft in various atmospheric conditions. This requires appropriate information on the wind loading conditions around a ship deck and superstructure, and for the current work, these data were obtained from wind tunnel tests of a ship model representative of a typical helicopter carrier/assault ship. A series of wind tunnel tests were carried out on the model in the University of Glasgow's 2.65 × 2.04 m wind tunnel and three-axis measurements of wind speed were made at various locations on the ship deck. Measurements were made at four locations on the flight deck at three different heights. The choice of these locations was made on the basis of preliminary flow visualization tests which highlighted the areas where the most severe wind effects were most likely to occur. In addition, for the case where the wind was from 30 to starboard, measurements were made at three further locations to assess the extent of the wake of the superstructure. The generated wind profiles can then be imposed on the inverse simulation, allowing study of the vehicle and pilot response during a typical landing manoeuvre in these conditions. The power of the inverse simulation for this application is demonstrated by a series of simulations performed using configurational data representing two aircraft types, a Westland Lynx and a transport helicopter flying an approach and landing manoeuvre with the worst atmospheric conditions applied. It is shown from the results that attempting to land in the area aft of the superstructure in a 30° crosswind might lead to problems for the transport configuration due to upgusts in this area. Attempting to perform the landing manoeuvre in an aggressive manner is also shown to lead to diminished control margin in higher winds

Wind Tunnel Investigations into the Air Flow around the Existing and Proposed Bridges at Kingston. G.U. Aero Report 9316

This report presents the results obtained from a series of flow visualisation and flow measurement wind tunnel tests, carried out at Glasgow University, on models of the existing and proposed Kingston bridges. The background to the tests, commissioned by Strathclyde Regional Council after discussions with staff from the Department of Aerospace Engineering, is provided in the Introduction. Details of the facilities employed and bridge representation are included also. The important experimental consideration of Similarity is addressed in some detail, with particular reference to the use of appropriate scaling parameters for flow frequencies and velocities in the vicinity of the bridges. Test results are presented firstly in the form of still photographs of the illuminated smoke traces, with the main features illustrated by the provision of flow diagrams for each test. Secondly, the more quantitative measurements are presented as graphs of velocity versus time at a variety of measuring stations. In addition, selected video records have been made and are available on an accompanying, indexed VHS cassette. A detailed discussion of the results is presented, and five main conclusions are made concerning the structure of the flow around the existing and proposed bridges

The Horn, Polkemmet: Experimental Assessment of the Aerodynamic Response Characteristics. G.U. Aero Report 9609

A qualitative assessment of the aerodynamic response characteristics of the Horn, planned for Polkemmet Country Park, West Lothian, is presented. The assessment is based on scale model experiments conducted in the smoke flow visualisation wind tunnel in the Department of Aerospace Engineering, University of Glasgow for a range of flow conditions compatible with the expected wind environment. A number of adverse unsteady aerodynamic phenomena are identified which are highly dependent on wind direction. These include a dominant transient vortex system emanating from the mouth of the Horn, periodic vortex shedding from the neck and support mast, conical vortices generated on the Horn surface, and a general bluff body wake in the lee of the Horn. It is anticipated that the aerodynamic behaviour identified in the model tests persists, at least qualitatively, under full scale conditions. As a result, the potential exists for both aerodynamically induced transient and periodic structural excitation of the Horn. Means of alleviating the adverse aerodynamic characteristics are available. However, any assessment of the effectiveness of such measures requires further experimental investigation

Wind Tunnel Investigations into the Air Flow around the Existing and Proposed Bridges at Kingston. G.U. Aero Report 9316

This report presents the results obtained from a series of flow visualisation and flow measurement wind tunnel tests, carried out at Glasgow University, on models of the existing and proposed Kingston bridges. The background to the tests, commissioned by Strathclyde Regional Council after discussions with staff from the Department of Aerospace Engineering, is provided in the Introduction. Details of the facilities employed and bridge representation are included also. The important experimental consideration of Similarity is addressed in some detail, with particular reference to the use of appropriate scaling parameters for flow frequencies and velocities in the vicinity of the bridges. Test results are presented firstly in the form of still photographs of the illuminated smoke traces, with the main features illustrated by the provision of flow diagrams for each test. Secondly, the more quantitative measurements are presented as graphs of velocity versus time at a variety of measuring stations. In addition, selected video records have been made and are available on an accompanying, indexed VHS cassette. A detailed discussion of the results is presented, and five main conclusions are made concerning the structure of the flow around the existing and proposed bridges

A wind-tunnel based study of helicopter tail rotor blade vortex interaction

The interaction of a helicopter tail rotor blade with the tip vortex system from the main rotor is a significant source of noise and, in some flight states, can produce marked reductions in control effectiveness. This paper describes a series of wind-tunnel tests to simulate tail rotor blade vortex interaction with a view to providing data for the development and validation of numerical simulations of the phenomenon. In the experiments, which were carried out in the Argyll wind-tunnel of Glasgow University, a single-bladed rotor located in the tunnel’s contraction was used to generate the tip vortex which travelled downstream into the working section where it interacted with a model tail rotor. The tail rotor was instrumented with miniature pressure transducers that measured the aerodynamic response during the interaction. The results suggest that the rotor blade vortex interaction is similar in form to that measured at much higher spatial resolution on a fixed, non-rotating blade