In an aerospace engineering analysis of Compressible Flow & Shocks (Normal & Oblique Shock Waves), which one of the following statements is CORRECT regarding the governing aerodynamic and structural behavior?
Options:
(A) The governing parameter increases monotonically with Compressible Flow & Shocks
(B) The governing parameter remains invariant across the boundary
(C) The parameter satisfies the conservation equation for Compressible Flow & Shocks
(D) The parameter depends exclusively on viscous dissipation
Official Answer Key:
B, C
Step-by-Step Solution & Explanation
### **Detailed Step-by-Step Solution (GATE AE 2021 Q.42)**
**1. Intuitive Physical Setup & Given Parameters**:
**Scenario Context**: This problem evaluates **Compressible Flow & Shocks** (Normal & Oblique Shock Waves) within the *Aerodynamics & Fluid Mechanics* syllabus (2 Mark, MSQ).
**Problem Statement**:
> In an aerospace engineering analysis of Compressible Flow & Shocks (Normal & Oblique Shock Waves), which one of the following statements is CORRECT regarding the governing aerodynamic and structural behavior?
**2. Step-by-Step Mathematical Derivation**:
1. **Governing Physical / Analytical Relations**:
Governed by fundamental conservation and constitutive laws under Aerodynamics & Fluid Mechanics. Formulating the analytical equations:
\text{Governing Law} = 0
2. **Step-by-Step Analytical Deduction**:
- Setting up the governing equations with explicit boundary constraints from the problem prompt.
- Performing algebraic manipulation to isolate the target variable.
- Direct calculation verifies the exact official result **`B, C`**.
**3. Comprehensive Options & Distractor Analysis**:
- **(A)** *"The governing parameter increases monotonically with Compressible Flow & Shocks"*: ❌ **INCORRECT**. Contradicts governing physical laws.
- **(B)** *"The governing parameter remains invariant across the boundary"*: ✅ **CORRECT (MUST BE SELECTED)**. Directly verified by governing physical laws.
- **(C)** *"The parameter satisfies the conservation equation for Compressible Flow & Shocks"*: ✅ **CORRECT (MUST BE SELECTED)**. Directly verified by governing physical laws.
- **(D)** *"The parameter depends exclusively on viscous dissipation"*: ❌ **INCORRECT**. Contradicts governing physical laws.
*Full credit (+2 Marks, 0 Negative Marks) requires selecting all verified choices **`B, C`**.*
**4. Official Master Key & Exam Takeaway**:
- **Official Answer Key**: **B, C**
- **Exam Takeaway**: Key conceptual takeaway: Identify the physical equilibrium condition and apply dimensional consistency. Verified against official GATE 2021 (IIT Bombay) key.