Yuzhnoye design office has a wide experience in aero/gas dynamic analyses. Using available procedures, Yuzhnoye can quickly and accurately determine aero/gas dynamic performance of space hardware and launch systems.

The procedures were successfully tested by solving a variety of engineering problems. The calculation data have a good convergence with test data.

Aerodynamic characteristics of launch vehicles, separating elements, and descent modules

Determination of total and distributed aerodynamic characteristics (Cx, Cy, my, mz) of launch vehicles, separating elements, and descent modules in all phases of operation.

Aerodynamic characteristics are determined for Mach numbers ranging between 0 to 20 and angles of attack ranging between 0 and 180°. The determination error is under 20 %.

Using available software, Yuzhnoye calculated aerodynamic characteristics of Zenit, Dnepr, and other launch vehicles designed in-house.

Gas flow modeling and parameter analysis in operating pneumatic systems

Yuzhnoye uses procedures developed for calculation and modeling of pneumatic-system gas-dynamic and time parameters. The procedures are used for determining

  • Bottle filling/emptying time, gas pressure and temperature variation,
  • Diameters of gas pipelines, orifices, or throttling devices,
  • Bottles volumes for various desired conditions,
  • Gas flow rate/velocity and mass for solution of engineering problems,
  • Pneumatic-system thrust characteristics.

The procedures take into account basic physical processes in pneumatic systems: heat exchange, compressibility, Joule-Thomson effect, as well as the type of gas and the supply line characteristics. These procedures can determine and optimize parameters of various pneumatic systems for desired conditions and requirements. They help to run experiments on model and full scale structures, and process and analyze experimental data, which saves design and development costs.

These procedures are used for quick and accurate determination of the change in gas dynamic parameters (pressure, temperature, velocity, flow rate) during various operations, purging of pipelines, control units, and fittings; and for reproduction of various nominal and off-nominal situations. The procedures were successfully tested by solving a variety of engineering problems, such as quick replacement of scarce gases with simpler, cheaper, and more available gases (replacement of helium with nitrogen or air).

The proposed procedures have been successfully used in design of different pneumatic systems for space applications. The calculation data have a good convergence with test data.

Determination of spacecraft aerodynamic characteristics, spacecraft characteristics in solar-wind flux, and solar activity prediction

Determination of SC aerodynamic characteristics in free molecular flow during orbital flight with and without attitude control; aerodynamic characteristics of launch vehicle stages in powered and coast flight in free molecular flow and in transition flow; SC characteristics in solar-wind flux during orbital flight with and without attitude control; monthly, quarterly, and 11-year solar activity predictions.

SC structural configuration can be visualized, with components displayed and their mutual influence taken into account; aerodynamic characteristics can be calculated for different positions of solar arrays and other components. Aerodynamic characteristics are calculated for arbitrary spacecraft orientation, quickly and with a reasonable degree of accuracy.

The procedures and software helped to determine aerodynamic characteristics and solar effect characteristics for more than 400 Kosmos and Interkosmos spacecraft and for Okean-О, LatinSat, SaudiSat, EgyptSat, and TerraSAR satellites. Solar activity is predicted on a constant basis to provide analytical support to satellites operating in orbit.

Determination of wind aerodynamic loads on launch vehicles

Total and distributed aerodynamic characteristics of rockets are determined with due account for effect of nearby launch facilities and structures and irregularity of the surface wind flow.

The following can be determined based on design and test data:

  • Aerodynamic characteristics (total and distributed) required for strength and stability analyses
  • Aerodynamic loads affecting individual rocket and launch facility components.

The characteristics determination error is under 20%.

This approach was tested during development of missile complexes, and it can be successfully applied to determination of aerodynamic loads affecting tall buildings and tower-type buildings in urban areas.

Determination of rocket gas dynamic characteristics at launch

Determination of a complete set of gas dynamic characteristics for various launch platforms: ground launchers, semi-buried launchers, sea platforms, silos, and for a mortar-style launch. The characteristics are required for high-quality design and testing of launch vehicles and launchers. The gas dynamic characteristics include shock and quasi-static gas dynamic loads on launch vehicles and launchers.

Maximum utilization of gas-dynamic measurements conducted on model rockets and launchers and on full-scale hardware provides highly reliable results.

Yuzhnoye developed a system of computer-adapted programs and procedures, including applications for calculation of gas-dynamic characteristics of mortar-style launch, ground launch, and semi buried launch; and calculation of gas-dynamic characteristics of exhaust plumes in initial and main phases of the flight profile.

Using available software, Yuzhnoye calculated gas dynamic characteristics of the Zenit, Dnepr, and other launch vehicles designed in-house.

Aero/gas dynamic design. Characterization of gases affecting spacecraft integrated into launch vehicles in all ground operation phases

Layout design and characterization of launch vehicle dry compartment thermal conditioning systems; assessment of gas dynamic effects and thermal behavior of equipment installed in the dry compartments, taking into account specific spacecraft or other equipment requirements.

The adopted procedure for assessment of parameters in thermally-controlled compartments significantly reduces costs related to dry-compartment thermal conditioning system design and payload integration and mission analyses.

Electronic simulation of flow in dry compartments is used as an input for an analysis of the possibility to accommodate dry-compartment equipment constraints. Main evaluation parameters are velocity and temperature of air flow near thermally conditioned assemblies, and thermal behavior of these assemblies. Main characteristics are verified by development tests at assembly- and system-level.

The methodology can be applied to design of ventilation systems and maintenance of temperature conditions in facilities such as clean rooms, shop floors, operator compartments. Required room cleanliness can be provided and ergonomic requirements met without a significant number of development tests.

Aerodynamic computation of horizontal- and vertical-axis wind-driven power plants

For specified power of wind-driven power plants and known wind characteristics:

  • General layout of wind-driven power plants is selected, and optimal geometry is defined
  • Total and distributed aerodynamic loads are calculated for a working velocity range and for extreme conditions
  • Relationship is defined between the wind-driven power plant power and rotor speed at different wind-speeds, which is the principal energy characteristic for wind-driven power plant control system design.

Aerodynamic computation of vertical- and horizontal-axis wind-driven power plants is conducted with consideration of the above conditions.

The calculations provide

  • Evaluation of aerodynamics of vertical-axis wind-driven power plants, which is the best from the control (wind orientation) point of view
  • Easy and user-friendly setting of input data; complete and clear results; minimum time for computer-aided calculation.

The developed program makes the most of experiment findings for wind-driven power plants.

Yuzhnoye proposes computer software for wind-driven power plant aerodynamic and energy computation, for design of best configurations with vertical and horizontal rotor axes, and for selection of optimal geometry for wind-driven power plants with specified power level.

Gas dynamic computation for payload fairing jettison pneumatic system

The developed computational program and procedure allow definition of parameters of a payload fairing jettison pneumatic system comprising a high-pressure gas bottle, control units, feed lines, and a pneumatic pusher. The definition parameters include:

  • Bottle pressure and temperature
  • Pneumatic-pusher internal gas pressure and temperature
  • Pneumatic pusher force.

During design, the procedure allows a quick and accurate selection of optimal characteristics of the payload fairing jettison pneumatic system for required pneumatic pusher parameters (initial force and performed work).

With preset pneumatic-system dimensions and pneumatic-pusher stroke, the bottle and pneumatic-pusher internal pressure and the force generated by the pusher are defined with respect to time.

Calculation results obtained by this procedure have a good convergence with ground and flight test data.

Analysis of generator system for pressurization of launch vehicle tank filled with nitrogen tetroxide

Yuzhnoye developed a program and procedure for analysis of heat and mass exchange processes inside oxidizer tanks during pressurization with NTO/UDMH combustion products at 200…500°C at k=16…22. The program evaluates

  • Gas pressure and temperature inside the tank
  • Tank structural temperature
  • Pressurizing gas and oxidizer vapor mass inside the tank
  • Warm-up of upper oxidizer layer in the tank.

The procedure considers features of gas inlet devices, dissociation of NTO vapors and their phase changes, heat and mass exchange processes, acceleration effects. Required flow rate and mass of the generator gas to pressurize the NTO tank are defined, as well as a set of pressurization system parameters. The procedure allows saving costs of the pressurization system design and development tests.

Calculation results obtained using the proposed procedure were confirmed by bench and flight test data.

Estimation of gas dynamic characteristics of stage and spacecraft separation. Gas dynamic design of separation and jettison mechanisms

The procedures define maximum pressures and loads applied by propulsion exhaust plumes onto surfaces of stages and spacecraft at separation.

The gas dynamic analysis programs use the correction trial coefficients obtained during research on models of separating stages and payload units.

The proposed procedures allow defining maximum gas dynamic loads applied by propulsion exhaust plumes onto surfaces of stages and spacecraft at separation.